Ryan and I were waiting for our older sister. She was working in the area and had invited herself to stay with us overnight, telling us she’d arrive by 6 pm. By 9:30 pm, she still hadn’t shown up and wasn’t answering her phone. I didn’t bother leaving a voicemail. I felt the ten missed calls already sent out a clear enough message.

I accidentally let out a grunt of frustration. ‘No luck with Rachel?’ asked Fiona.

‘Nope,’ I said. ‘It’s typical.’ I tried not to let my annoyance show, but I couldn’t keep a lid on it much longer. ‘It’s getting out of hand. She’s always liked a drink after work, but it’s got worse over the last year. It’s every night now. It’s taken over her life. She’s late for everything.’

‘Is she getting any help?’

‘None at all. Mum and dad have tried to talk to her, but she just denies having a problem.’

‘Must be tough.’

Our doorbell rang and I jumped up to answer it. I was met by two women holding Rachel upright. Predictably, she was hammered. One of them thrust a plastic bag into my hand and said, ‘I believe she’s staying with you.’

‘Oh, for God’s sake,’ I said, taking the bag and helping Rachel inside. ‘Thank you so much.’

They weren’t interested in thanks. Instead, they walked off without a word. I couldn’t blame them.

Rachel leaned against the wall in the hallway and I shut the door. ‘That was my colleagues. Did you know one of them writes erotic stories? Calls herself Jenna Side. Get it? Like genocide? Says it’s all about wanking and stuff.’

Even though I was four years younger, I sometimes had to act like the older sister. ‘We all have early classes tomorrow and you need your bed.’ I gestured in the direction of the smaller bedroom, which we didn’t normally use.

‘Happy birthday, Ryan,’ said Rachel, ‘I’ve got something for you.’ She pointed at the bag I was holding. I looked inside. It contained a bottle of rosé prosecco, freshly bought from Tesco, as shown by the receipt in the bag. I handed it to him.

‘Get to bed. We’ll talk in the morning.’

With a huffy sigh, she stumbled into the bedroom and slammed the door behind her.

‘Bedtime for me,’ I said to the other two. ‘You can come if you want to.’

‘Are you okay?’ asked Fiona.

‘I’m glad you talked me out of putting my bed in there. I don’t want to spend another minute with her like this.’

Fiona and Ryan decided to join me. Twenty minutes later, we’d all cleaned our teeth and we ladies had our pyjamas on. Ryan was still naked because he was the only one of us in the mood to masturbate that night. He was still in love with his vagina-like toy, so he set it up on his half of the double bed. He squirted some lube in it, plus a little on his own erection before inserting it. To stop the toy from moving backward when he thrust into it, he would place a cardboard box between the back of the toy and the headboard, although the box was fast becoming crumpled.

Normally, the sight of my brother pleasuring himself could start my juices flowing, but it was doing nothing for me tonight and Fiona didn’t seem turned on either, so we let him do his business while we talked. Fiona had recently been talking about visiting the boys again. They’d been absent from our group because Thomas had objected to my brother and me having sex.’

‘I really think,’ she said, ‘if we pay them a surprise visit and just talk to Thomas, we can talk him round and we can go back to having our little orgies.’

‘I don’t think it’s as easy as that. He can be stubborn.’

‘Steven’s fine with it; everyone else is fine with it. The only reason he doesn’t come is that Thomas made him choose between staying in the group or being his boyfriend. It’s a hell of a position to put him in.’

‘But if we go round all guns blazing, he’s hardly going to…’

As I spoke, Rachel burst into our room. Ryan hadn’t finished yet but withdrew from his toy, picked up a pillow, and held it in front of himself. It was too late to stop her from seeing his erection.

‘I am not ready for bed yet,’ she said, pointing at the floor to emphasise each of her words. As she walked towards Ryan, I noticed she’d taken off her leggings and had only a T-shirt on, just long enough to cover her vagina. Judging by the jiggle of her boobs underneath, she wasn’t wearing a bra either.

‘Happy birthday, Ryan.’ She took him in a bear hug and kissed him on the lips. He didn’t kiss back. Instead, he opened his eyes wide in shock. He continued to hold the pillow tightly in front of him. She broke the kiss, keeping one arm around him. With the other, she alternately pointed at him and me. ‘What do you two see in each other? I know you still… do it, but what do you see in each other?’

‘Let him go,’ I said. ‘Go to bed.’

‘I’m not going to bed. We’re going to talk about this right now.’

‘Talk about what?’

‘You and him.’ Rachel turned to Fiona. ‘You know all about this, right?’

Fiona nodded.

‘Fine,’ I said. ‘If we’ve got to talk about it, remember you let him finger you once and you didn’t like it.’

‘That was, what, two years ago? Maybe I didn’t let him go far enough. You clearly see something I didn’t get from him, so I think he and I need to do it.’

‘Rachel,’ I said, ‘let him go. Let this go.’

‘Are you telling me not to do anything with him? Well, that’s double standards from where I’m standing.’

I couldn’t argue that point, but I could delay them. ‘At least wait until you’ve sobered up. If you still want to do it tomorrow, then be my guest.’

She waved her hand dismissively. ‘I just want to know.’

‘You’re not doing anything with him tonight.’

She looked Ryan in the eyes. ‘You want to do it, right?’

‘Um…’ he started, but Rachel interrupted.

‘Because,’ she reached down behind the pillow, ‘you’re still hard and that tells me you want to do it.’

‘Well, yes. But not…,’ he started.

I interrupted. ‘Just leave it one night and think about it.’

Not listening to me, she tugged his arm and led him to the second bedroom.

‘Just wait one night,’ I shouted after them. They closed the bedroom door behind them without an acknowledgement.

‘Well, it’s up to them now,’ said Fiona.

‘I don’t suppose he’ll be needing this now.’ I took the vagina-shaped toy and the cardboard box off the bed and placed them in a corner. ‘I don’t know what to say, Fiona. I really don’t. She needs help. For the drinking, I mean. I can’t exactly have a go at her for the incest.’

‘You and Ryan did it sensibly, though. You talked about it first.’

‘And she won’t even admit she has a problem. And I don’t know about her, but I need to go to bed at a reasonable hour, but I don’t know how long they’re going to take.’

‘Let’s give them half an hour or so. If they’re not finished, we’ll go and check on them.’

But we waited less than ten minutes before my sister burst back into the room holding Ryan’s hand. She was still wearing her T-shirt, while he was naked and holding his erection with his free hand. She turned to our brother and told him to lie face-up on his half of the double bed.’

‘Wait,’ I said, ‘you’re not doing it in here.’

‘We tried it on that mattress, but it isn’t going to hold up.’

‘That’s enough. Just leave it tonight. You go back to bed next door, he’ll be sleeping in here, and we can talk about this in the morning.’

‘I just want to see what you see in each other.’

‘This isn’t the time. You’re drunk. You have a boyfriend.’

She lowered herself onto our brother’s penis. ‘I have had barely anything to drink tonight. I know what I’m doing.’

Then Fiona raised a point that hadn’t even occurred to me. ‘At least use a condom. I’ve got a spare one here.’

‘Don’t need one. I’m on the coil.’

‘Rachel!’ I tried again. ‘Just play it safe this once. He could get you pregnant if it fails.’

‘Same could happen to you.’

I wasn’t in the mood to argue. ‘Has it ever let you down?’

‘No.’

‘Are you sure?’

‘Never let me down.’

‘If you say so, but I think he should put one on.’

She didn’t respond to that, instead focussing on thrusting up and down on Ryan. I didn’t want to watch, but I couldn’t turn away. I could see the sheer delight across the face of my 20-year-old brother as he sank ever deeper into her. He was taking as much sexual pleasure from his 26-year-old sister as he usually would from his 22-year-old sister and his reaction was making me wet.

After a short while, Rachel slipped a hand under her T-shirt and touched the opposite boob. I couldn’t see anything clearly, but I was almost certain she was squeezing it. I was impressed by her ability to keep his penis inside her despite her quick up-and-down motion. When I went on top with any guy, it constantly slipped out.

Without taking off my pyjamas, I fingered myself without my vibrator. I was within reach of my siblings, so I touched Ryan’s nearest nipple with my free hand. While still masturbating, I found myself leaning in and kissing the other nipple, then his lips, using my tongue as well. Lifting herself up a little, Rachel moved the hand to the opposite boob, and this time I could clearly see her squeeze it through her T-shirt. Her other hand went to her clit.

Fiona wasn’t masturbating but was watching them with interest.

I saw my brother’s face screw up slightly, knowing he was about to shoot. The thought helped push me over the edge and it looked like our sister was climaxing as well, completing our triad of sibling orgasms. Rachel lifted herself off him and fell to the side. Fiona handed over some tissues so they could wipe up the mess.

Now a little tired, I took control again. ‘Right, Rachel. You go next door. We’re going to talk about this in the morning.’

But her earlier burst of energy seemed to disappear as quickly as it arrived, and she was already asleep.

‘Change of plan,’ I said. ‘Ryan, you go next door. I’ll go next to Rachel and make sure she’s all right. Fiona, you can have my bed.’

‘Why me?’

‘I’m not arguing. On you go. We all have to be up tomorrow.’

As he left the room, a thought occurred to him and he smirked. ‘I’ve had sex with both my sisters. How many guys can say that?’

‘Go. We’ll talk about this tomorrow.’

He left the room.

‘Then,’ said Fiona, ‘can we talk more about seeing Thomas and Steven?’

In the short time since we’d last discussed the matter, I’d changed my mind. I wanted my boys back as much as her. ‘Yes. Yes, let’s go and see them as soon as we can.’