At around four o'clock, I met my little brother at the railway station. I checked around me, and when I was reasonably sure there was nobody we knew, I took a calculated risk and kissed him quickly on the lips, which turned me on.

The first question out of his mouth was, 'Where's Fiona?'

'Ryan! Not even a "How are you?"'

'How are you? Where's Fiona?'

'You're a cheeky boy, aren't you?' I helped him with one of his bags as we walked to the exit. 'She's got a shift until six, but you've got all weekend to see her, so calm down.'

'I thought you worked in the same bar?'

'Sometimes we get different shifts. Anyway, you've got a girlfriend.'

'We broke up.'

'With Cheryl? Didn't you only just get back with her?'

'It wasn't working out.'

'I'm sorry to hear that.'

I'd wondered what to do with him until Fiona returned. She'd offered to cook for us tonight, so we didn't need a meal, and if we went straight home, we'd probably spend the next two hours in bed together catching up.

So I'd already decided to take him for a walk down to the beach. We were carrying his luggage, but it wasn't far to travel. It was also freezing, so I'd brought along a spare hat and scarf for him. We had the place almost to ourselves, and we sat down with takeaway cups of tea.

He used the privacy to his advantage, asking again to join my masturbation group with Fiona and our boyfriends.

'I've said no before, and I'm saying no again. I'm sure it would be great to have you there, but we need to keep our fun separate from what I do with the group.'

'But you've said it's okay for me and Fiona to get together this weekend, even if you're there.'

'That's different. You've slept together before, and she knows how close we are. I mean, she doesn't know everything, and I'd like to keep it that way, but the wider group wouldn't understand.'

'They would. You've told me Jack and Samantha are brother and sister, so it's not like we'd be the first.'

'As I've also said, Jack and Samantha don't do anything together. They're both gay.'

'And what about the cousins you went to school with? They became a couple.'

'That's frowned-upon, but it's not illegal.'

'I don't get it. We wouldn't have to do anything together. We could still keep that a secret.'

I tried a different angle. 'There would be other boys there as well, and they'd all be wanking and having sex with each other.'

'I don't mind. I just think it would be really good to join in with everyone. I'm going to be moving to your college anyway. It just makes sense.'

Ryan was on the verge of leaving school, and had wanted to move in with me and Fiona. Financially, it would have helped a great deal, but the flat was barely big enough for two people, never mind three. I was actively looking for a bigger place so he could join us.

Latching onto his last comment, I tried to change the subject. 'Have you heard back about your accommodation?'

'I've got a place on campus and it turns out I know one of the other guys already, and he's going to bring his dartboard and a ping-pong table, and what we're going to do is get some decks and disco lights so it's like a club...' 

He went on like this for some time. The more he spoke, the more he sounded like every student cliché rolled into one. Furthermore, he was so wrapped up in these plans that it was clear he hadn't listened to a word of advice I'd given him about the practicalities of living with strangers. 

I was about to interrupt his monologue to repeat my points, but I stopped myself. When he was talking about his laughable plans, he wasn't asking to join our group. Then he moved on to how great it would be for meeting women, and moved back to the topic of Cheryl.

'It just wasn't working out. She was always at her office, and I never got to see her.'

'What did she work as?'

'Call centre for the tax office. She was always getting asked to do overtime and never ever turned it down. We're still friends, though.'

'An important job, I'm sure. That's good you're still friends. Are you looking for a part-time job as well?'

He wasn't paying attention. 'We only had sex about three times. Did you know she didn't masturbate?' I was shocked at him mentioning this, not because of what he said – we often told each other such details – but because it came out of the blue.

'Really?'

'Didn't even have a vibrator.'

'I'd go mad.' It was clear he wanted to get back onto the topic I'd steered him away from, and I should have stopped there and changed the subject again. Instead, I stupidly added, 'There was one girl at my school who didn't: Maria. She would sit out while the rest of us did it.'

'Well, I guarantee I wouldn't sit out. I don't care if you have other boys there, I really don't. I just want to join in with you all.'

'No, Ryan. It's not happening. You and I can have fun in secret, or you and Fiona can do what you always do, but you're not joining our group.'

'That's not fair.'

I saw he'd finished his tea so I took his cup. 'Sorry, but that's final, but you and me in private? No problem.' I quickly checked we were still alone, then kissed him to reinforce my apology. Like the kiss at the station, that one also turned me on and I suddenly couldn't wait to take him home. It was probably because we'd both agreed not to orgasm for two days before his visit.

I tried not to seem too keen. 'That's coming up for five o'clock already. 'Let's start heading back.'

There was a toilet block next to the beach. As we passed, I seriously considered taking advantage of the quietness and sneaking him into the Ladies for a bit of fun. I thought better of it; there was still a small risk of being caught, and a bus home was about to arrive.

We sat together upstairs near the back. Through his trousers, I couldn't resist discreetly squeezing his penis, which was solid. I let him slip his hand under my top; his palm was freezing but it was pleasant to feel him all the same.

Back at my flat, the only question was who would initiate first. I barely had time to drop his bag and lock my door before Ryan placed a hand on my backside; if he hadn't, I would have done it to him. I squeezed his erection again and brought him in for a deep French kiss before leading him to my bedroom.

'Right. This is just to take the edge off it, so no orgasms for you. You might need your load for later on, for Fiona.'

'That's okay. I can come twice.'

'You've said that before and it doesn't always happen.'

We took each other's clothes off as we spoke.

'It's fine. It'll happen this time, definitely.'

'We've had this conversation so many times.'

'I just want to spunk. I haven't wanked in two days.'

'Neither have I. You can wait a bit longer.'

With us both topless, I started grinding my panties against the bulge in my brother's boxer shorts. When we did anything more than kissing, there was an unspoken rule to look away from each other. It meant both of us could enjoy the feeling of the other person while fantasising it was someone else. Penetration, for example, was almost always from behind to avoid eye contact.

We'd done this for a couple of minutes before I realised my bedroom curtains were still open. The window looked onto a path that wasn't very busy, but if anyone had been out at the bins, they would have had a front-row seat for some incestuous foreplay.

'Please,' he said as I stood up to close the curtains. 'I'll do it myself if you won't.'

I sighed. 'Are you sure? Absolutely sure? If Fiona's in the mood, you might only have to wait a few more hours.'

'I'm still sure.'

'All right, then, but I'm going to get you off by hand, no sex.'

'Oh.'

'I know you want inside me, but you'll just tire yourself out. I know how hard you thrust.'

He let me lie beside him, pop out his erection and wrap my fingers around his foreskin in just the way he liked. I slipped my other hand down my panties to touch my clit, exactly in time with what I was doing to him. 

As we looked away from each other again, I warned him, 'If you can't get it up with Fiona, don't come crying to me.'

'It'll be fine.'

It only took another couple of minutes before I felt a ton of white fluid shoot onto the back of my hand. I pinched the base of his penis and moved my hand slowly all the way up to the top, squeezing out anything still inside him.

'You clean up,' I kissed him on the cheek, 'and I'll finish myself off.'

As he left the bed, I made sure his semen didn't drip off my hand. For about two years, after lots of experiment and practice, I'd been able to reliably experience female ejaculation, and I always swallowed my own fluids. But here, I had a rare opportunity to taste both of us together.

I moaned as I squirted into my playing hand, which I cupped, while any stray drops were caught by my panties. I carefully moved both hands to my mouth, licking the fluids from each so they mixed together. I savoured it a little, then swallowed the lot.

'Was that nice?' he asked, cleaning off his half-erection.

'Always. Grab me a tissue as well.'

Once I'd wiped up, we both washed our hands and were enjoying a final kiss when Fiona opened the front door. Fortunately, she was too preoccupied with several carrier bags to notice us rapidly pulling away from each other.

'Drinks,' she said, pushing past us to place the bags in the kitchen. We followed her there.

I always found it interesting to watch their different flirtation styles. He was about as subtle as a brick through a window. 'Hello again. It's really great to see you again. That's nice perfume you're wearing.'

She, by contrast, would turn on the charm just a little and didn't always rise to his come-ons. She ruffled his hair gently as she unpacked the bags. 'I hope you're hungry, Ryan, because I've got a massive appetite tonight. I also have some wine.' She pulled out several bottles. 'Red, and some prosecco, and... whatever this is; it was on offer.'

'I don't like wine. You got any beer?'

'Hold your horses there,' she replied, sounding like a voiceover from an advert. She placed another bag on the worktop. 'According to recent research, young men aged eighteen to twenty-four don't drink wine, and this is the most popular lager brand among that demographic.'

Us ladies burst out laughing, and it quickly turned into an in-joke. For the entire time we cooked and ate the stir-fry, we called him Young Man Aged Eighteen to Twenty-four.

'Right, you can both stop it now,' he kept saying.

After dessert, he was squeezed onto the small couch between Fiona and me, with his arm around her. She wasn't responding to that directly, but was occasionally brushing his arm or his leg, or making knowing eye contact before looking away.

'Stop what, Young Man Aged Eighteen to Twenty-four?' I said.

'Can I try your wine?'

'No, you turned it down. As a Young Man Aged Eighteen to Twenty-four, you statistically don't like wine. Fiona's a media student; she knows these things.'

He sulked with his third beer in his hand and pretended to watch Coronation Street. We'd turned on the TV earlier, but nobody was really watching it. I thought it would be wise to bring up the sleeping arrangements again. I mainly addressed Ryan.

'To make sure we're all on the same page, you'll be on the inflatable mattress between our beds. Now, Fiona and I are comfortable being naked around each other and doing sexual stuff in the same room, so you can both masturbate or do other stuff if you want.'

'Wey-hey, sounds good to me,' said Ryan, predictably.

'Woah. Are you sure about this? I know you and Young Man Aged Eighteen to Twenty-four are close, but you honestly don't mind us doing stuff? While you're here?'

'Stop calling me that.'

'We all have needs, and it's not like me and him are going to be doing anything. Anyway, I've been wet all day, so I'm definitely giving myself an orgasm tonight.'

My brother let out a performative, 'Eww.'

She brushed his leg again and smiled. He placed his arm a little more securely around her. I hoped he would be able to recharge in time to have a little fun.