I come down for breakfast the next morning and find Katie and Aoife already at the breakfast bar, munching their way through the crunchy nut cornflakes. Katie blushes and smiles sheepishly, watching me over the top of the cereal box. Images of last night flood my mind as I lick my lips instinctively, imagining I can still taste her flavour on my tongue. She’s wearing the same pair of too-tight pyjamas, the ones I had stripped from her before sucking her tits and making her cum on my face.

“Good morning, Mammy,” Aoife calls, and I drag my focus away from Katie to smile at my sixteen-year-old daughter.

“Morning, darling. What are your plans today?”

I begin making a cup of tea as Aoife tells me she and Katie are going shopping.

“We should be back before tea.”

“We?”

“Well, Mummy is away still, and I thought you’d have loads of work to do, so I asked Katie if she’d stay over tonight again.” She beams at me like this is the best news in the world. “And Katie’s mum said yes, she could.”

She turns and smiles at Katie then the two of them look at me, beaming. Katie bites her lip as she stares at me.

I grip the worktop edge for support.

“Oh, did you, now? Well, since it’s all been arranged, there’s nothing I can do, is there?”

Aoife smiles triumphantly. “Nope.”

I drop the teabag in the sink and look for the milk. It’s on the table by Katie.

“Katie, be a good girl and pass me the milk.”

The words are out of my mouth before I realise. I see a glint in Katie’s eyes as I call her a good girl and she blushes, swallows and hands me the milk. Our fingers brush momentarily as I take the milk carton from her and I feel a frisson run through me.

“Right, well, we’re going to get ready, and then we’ll be off.” Aoife jumps off the stool. “I’ll shower first, Katie. You stay and finish your breakfast. Then you can shower after me.”

Aoife drops her bowl in the sink and heads out, leaving the kitchen door open. Neither Katie nor I say a word until we hear Aoife’s feet pound up the stairs and go into the bathroom.

“Good morning, Mammy,” Katie whispers.

“Katie, please... Last night… it shouldn’t have happened.”

Katie blushes but doesn’t look away. Her green eyes bore into me.

“But it did happen, Mammy. My pjs are still stained, look.”

She stands up and slides down her shorts. The sight of her red curls and the cum stains on the inside of her shorts are too much.

‘I’m sorry, Clodagh,’ I internally apologise as Katie steps closer. She wraps her arms around my neck and rises up on her tiptoes and kisses me.

“I want to be your good girl, Mammy,” she whispers as she kisses my jaw.

I try to be strong, try to resist her but how can I? Her soft plump lips caress me. Her hands slide over my breasts and down to my hips. She presses herself against me, and I can feel her nipples hardening as she rubs her breasts against me.

I put my hands on her arms and look her in the eye.

“You want to be a good girl, do you?”

She nods, not quite sure about the change in tone.

“Well, good girls do what they’re told.”

I turn her and press her against the wall. We are both aware of the sound of running water as Aoife gets into the shower. I press my forearm against Katie’s back and push her breasts and the side of her face against the kitchen wall. With my other hand, I tug her shorts down to the ankles, then tap on one ankle and tell her to spread her legs wider.

“Yes, Mammy,” she whimpers and instantly obeys. Holding her with one hand, I run the fingers of my other hand up her thigh and over her ass. She has such a delicious tight teenage ass and so so fuckable.

“What are you doing, Mammy?” she questions breathlessly.

I don’t answer. Instead, I brush her long red hair to one side, exposing her neck. I kiss it, tongue flickering behind her ear as my fingers stroke higher and higher up her inner thigh.

“Oh, God, Mammy,” she whimpers. I can feel her lips are damp. My fingertip glides between them and I smear the juices that ooze out of her along her slit.

“Are you going to be a good girl?” I whisper in her ear as I push a finger inside her.

“Fuck, yess, Mammy,” she gasps, pressing her ass back into my hand.

I move my finger quickly, both of us keeping an ear out for the shower. She writhes on my finger as I press it in deeper. Her wet velvet walls stretch as I take her.

“You’re such a good girl,” I whisper as she grinds back against my hand. I hold her hair, tugging on it, stretching her head back so she looks up at me.

We lock eyes. Her lips are parted and she’s breathing heavily as the sensations pulse through her. I can hear my finger squelch as I move it faster. She whimpers little fuck fuck noises as I fuck her deeper, harder and faster. She begins to writhe, impaled on my hand. Her legs shake as I take her, as she gives herself to me, as I push her over the edge.

She spasms just as we hear the shower switch off. She bucks and jerks like a marionette, a puppet I control with ease as her juices flood my hand. I clamp my hand over her mouth as she cries out and I can hear her muffled squeals as she cums for me.

Finally, she slumps back against the wall and I ease my finger out of her tight little fuck hole.

“Good girl,” I whisper. “Now run upstairs and clean yourself up in the shower and not a word to Aoife, understand?”

“Yes, Mammy,” she sighs with happiness. “I promise. It’s our secret. I’ll be a good girl for Mammy.”

She gives me one last passionate kiss before she pulls her shorts back on and scoots up the stairs.

Once the red mist clears, I grab the bar of soap and wash my hands at the sink, trying to remove every trace of Katie from my fingers. What the fuck am I doing? I scold myself. I know this is crazy. We can’t carry this on without Aoife noticing, and Clodagh will be back tomorrow. I must be crazy to risk all of that just because some little slut wants me to be her Mammy.

I resolve to put an end to it tonight. We’ll have a talk when Aoife is asleep and clear the air. She’ll understand. I know she will.

The girls come down thirty minutes later and I feel my resolve begin to crumble immediately. Katie is wearing a tight little sleeveless red top and a pair of black jeggings which are so tight I can nearly see the camel toe between her legs. And then I notice the black choker around her neck. How can someone so young be so fucking hot? I question. How does she know my buttons?

“Doesn’t Katie look amazing? I love her outfit, Mammy” Aoife runs her hand down Katie’s arm and I feel suddenly protective. I want to call out, “She’s mine, Aoife, keep your hands off her.”

“Can I get a necklace like hers, Mammy?”

I raise an eyebrow. “I’m… um… not sure they sell those in town,” I lie, trying to stall.

“No, it’s ok. They do. The shop behind the arcade has all sorts of necklaces and stuff.”

I know the shop she means and they are both too young to be going there. But I don’t want a blazing row with my daughter in front of Katie so I merely nod instead.

“Can I have money for one?”

I open my purse and hand over a twenty.

“And we might want to get some lunch too?”

I look at Katie who just smiles and runs her finger along the choker. Images of her wearing just the choker and nothing else as she kneels in front of me spring unbidden into my head.

I snap back to reality. Aoife is looking at me with her hand out. Wordlessly. I hand over another twenty.

She smiles and kisses me on the cheek. “I love you. You’re the best, Mammy,” she tells me and skips out the door.

“Come on, Katie, let’s go.”

“I love you too, Mammy,” Katie whispers and blows me a kiss before following my daughter out the door.

I can’t concentrate on doing any of the assessment work I was planning on doing so grab the hoover and decide to spend Saturday in a cleaning frenzy instead.

I’ve cleaned the bathroom, our bedroom’s been hoovered, Clodagh’s clothes are tidied away, and the room is spick and span. I open the door to Aoife’s room and stare at the chaos. It looks like every drawer has been emptied as they searched for clothes or whatever. I’m just about to close the door again and pretend I never saw the mess when I see Katie’s pj shorts lying on the bed.

As if on autopilot, I step into the room and pick them up. I bring them to my nose and inhale. The memories of last night and this morning collide as I smell Katie’s cum stained shorts. The heady scent of needy unbridled lust swirls around my head. My hand slides of its own accord inside my jogging bottoms and over my black cotton knickers.

I visualise Katie as I begin to rub. I see her last night, burying her face in my shoulder as I finger her to her first orgasm; I see her writhing in the bed, her face buried in the pillow to muffle the squeals as I use my tongue to bring her to a second, and I remember how I took her this morning, slammed against the wall with these very shorts around her ankles as I slammed my fingers deep inside her and told her what a good girl she was as she came for me again.

It’s so very, very wrong, but I can’t help myself. Katie is like a drug, and I’m constantly chasing my next fix. I’m rubbing faster now. My hand is inside the waistband of my knickers. My middle finger circles my clit as I inhale her scent once more.

I hear the front door bang shut and a pounding up the stairs. I pretend to be tidying up as they get nearer. They burst into Aoife’s bedroom and stop short, surprised to see me.

“What are you doing, Mammy?” Aoife stares accusingly at me. “I hate the way you just barge in here.”

“Well, if you didn’t leave it in such a pigsty, maybe I wouldn’t have to,” I retort. I know my face is flushed.

Aoife is wearing a choker too. I glance from her to Katie and back again. The two of them are wearing black collars. Fuck.

Katie is smiling at me as she stands behind Aoife. I wish she wasn’t here. I can’t seem to function properly when she’s around. I’m trying to be rational with my daughter, and all the while, her best friend, the best friend I’ve already fucked so many times this weekend, is standing watching, knowing what I am and what I’ve done.

“Fine, clean up your own mess then.”

It’s only then that I realise I’m still holding Katie’s pj shorts. Katie looks at them, then at me, then reaches over and takes them from me. I blush and try to open my mouth to speak but falter. Instead, I just walk out and go to my room and slam the door in a fit of childish pique.

I sit on the edge of my bed with my head and my hands and curse loudly. “Fuck.”

I wish Clodagh was here. She has a much better relationship with Aoife than I do. She’s much more able to control her. Maybe it’s because she’s not Aoife’s mother, but Aoife is never as bratty with her as she is with me.

I lie back on the bed and stare at the ceiling. I take out my phone and send Clodagh a quick text.

Missing you loads. Wish you were here. A is being a bitch.. again lol hurry home. S xxx

I stare at the screen for a while, but there’s no response. Not that I expected one. Clodagh was at some pharmaceutical conference and would have her phone switched off as she was that kind of woman; courteous, conscientious. She wouldn't want someone’s phone going off during her presentation, so why would she risk it happening during someone else’s talk?

It was on our third date that I finally brought up the fact I was a single mum. I reassured her that the dad wasn’t and had never been on the scene. I’d had a one-night stand that had only confirmed that I was definitely a lesbian. It was only weeks later that I realised I was pregnant and had no idea how to find a guy I think was called Gary. I’d met him in a club, and we’d fucked before we’d even got as far as exchanging either surnames or phone numbers. And so, I’d brought up Aoife alone until Clodagh came on the scene.

By teatime, I’ve calmed down. I’ve worked it out in my head. I’ll tell Katie she’s very special but what we are doing is wrong and has to stop. That it would destroy her friendship with Aoife and she might never forgive her. It would also destroy my marriage and that’s a lot for her to bear responsibility for. I realise as I’m deciding this that I’m coming across as a right bitch but I’m thinking tough love might be the way to go about this. I just need to get Katie alone for a few minutes and it can be all sorted.

“Girls, it’s teatime.”

I’ve made chicken nuggets and chips. Easy finger food. I pour a glass of red and have already necked half of it by the time Katie comes downstairs on her own.

“Aoife says she’s not hungry, and she’s not coming down. She’s very upset that you invaded our privacy.”

Katie pauses, having delivered her, or Aoife’s speech. I shrug and empty the glass. I reach for the bottle, about to pour another, when Katie speaks again.

“She’s not being a very good girl, is she, Mammy?”

I turn and look at her. Katie is standing there, biting her lip and stroking her choker. She steps closer and drops to her knees.

“I want to be Mammy’s good girl.”

Her fingers tug at the waistband of the jogging bottoms I’d worn for cleaning. They slide down easily, and Katie’s face presses into my damp knickers.

“Let me be your good girl, Mammy,” she whispers as her tongue licks at my crotch.

All the good intentions, all the speeches I had prepared, go out the window as Katie unpeels my knickers and licks at my glistening wet slit.

“Oh baby, you are definitely Mammy’s good girl,” I groan.

My fingers grip her hair and I push her face into me. I grind my hips, using Katie as she kneels there and licks and kisses my pussy. She kneels there and gazes up at me as she swirls her tongue along my slit. She French kisses my pussy as I squirm on her face.

I use her, almost like a masturbatory aid, as a fucktoy. I buck and jerk my hips and fuck her face as she kneels there. She’s so docile and compliant. I smear my juices over her face, marking her, claiming her as she licks and laps at my quivering pussy.

It builds so quickly. There’s an urgency that Aoife might change her mind and come down at any minute or she might wonder why Katie is away so long. Either way, I know we don’t have much time. I grip her head in both hands and facefuck her. I rub faster and faster against her mouth until my orgasm explodes over her.

She kneels there, not flinching as I spasm on her face. Finally, when she has drained me, I tug on her hair, pulling her face out of me. Her eyes sparkle. Her face glistens, covered in my creamy mess. She runs her tongue over her lips, scooping the smears of cream onto her tongue.

“Was I a good girl, Mammy?”

She climbs to her feet and kisses me. I taste my flavour on her tongue as she pushes it into my mouth.

“Yes, you were,” I whisper hoarsely. “You were such a good girl for Mammy.”

She picks up the plates of cooling chicken nuggets and chips.

“Good,” she smiles. I’ll take these up and see if Aoife will eat some, Mammy.”

I watch as Katie turns, traces of my cum still visible on her face.

“Wait,” I cry and with the small part of my brain still functioning rationally, I grab the kitchen roll and clean the cum smears from her face.

“Good idea, Mammy,” she whispers conspiratorially. “We don’t want Aoife to know.”

She kisses me on the cheek and heads up the stairs.

I pour another glass of wine and knock it back.

“What the fuck am I doing?” I groan.