Once a week for most of the school year, the boys had been squeezing into our changing rooms for what they called Wank Wednesday.

It was exactly what it sounds like. After games class, we'd been watching each other masturbate. It was originally a female-only group, but the boys were allowed in at the suggestion of my friend Tiff, and it turned me on a lot.

Fortunately, the teachers always kept their distance so we had some privacy. Unfortunately, we'd reached our very last Wank Wednesday before the summer break. After that, some of my classmates would be leaving school and going to college, and others didn't want to continue our sessions.

We'd all agreed not to masturbate at home for the week leading up to the final day. At the same time, though, we were a group of seventeen-year-olds and it quickly became clear we'd each only managed to hold off for a few days at most. I'd lasted until Saturday afternoon, then again for two days until I had to relieve cramps on Monday night.

Not everyone in our group would orgasm, though. Thomas claimed to be able to manage it at home, but he was never able to make himself hard enough in front of everyone else. And Maria said she didn't masturbate, so she'd never joined in, but she'd also never stopped us from having fun.

The session started off as it always did: we took off our games kit and headed to the showers. There was no touching each other allowed, but we would always stroke ourselves to stay aroused as we washed and dried off.

The highlight of Wank Wednesday would be the cousins Kath and Michael. At first, they didn't want to even see each other naked, but they were now competitive about who could orgasm first, and they had an exact fifty-fifty track record. For the deciding contest, we let them go before everyone else, but to keep it fair, neither of them were allowed to touch themselves for one minute before they started. In that time, I noticed Michael's erection go down under its own weight, but Kath still had a strong lady boner.

We counted down from three as the cousins sat facing each other, making eye contact. When we said, 'Go', they both grabbed their own genitals and quickly found their own rhythms, watching each other as they did so. Within twenty seconds, Kath was holding her breath and twitching with orgasm while Michael had only just made himself hard again. Some of the boys accused her of faking it, but females always know when another female genuinely gets off.

As Kath felt her orgasm fade, she pulled out two pencil erasers. She'd slipped them inside herself earlier to keep herself stimulated, then threw them at him with a smirk. Meanwhile, Michael squirted a load of semen on his stomach, more than I'd ever seen, and he retaliated straight away by scooping it up and throwing it at Kath, hitting her boobs and splashing on her face.

The boys shouted it was unfair for Kath to put something inside her, but the girls said there was no rule against it. We all went, 'Ewww,' at the semen, but I knew women liked to swallow it, and I secretly wished I had that chance. Kath went to wash herself off, and Michael followed her.

Now the rest of us could start touching ourselves. My clit had softened slightly while watching the cousins, and just as I made it fully hard again, I heard a voice from the corner say, 'Do you mind if I join in?' and it was Maria who'd spoken. Between moans, the girls said of course she could.

She slowly unwrapped her towel and started on her clit. She explained she'd never seen the appeal before but she'd been watching us the last year and seen how much we'd enjoyed ourselves. She added she'd been trying to reach orgasm herself and had succeeded a couple of times.

Usually, we restricted ourselves to one orgasm so we didn't take too long and didn't make the teachers suspicious. But the rule seemed to go out the window as the girls kept going and going, letting out days of sexual frustration.

It's a shame for boys that they'll never know the joy of having second and third orgasms straight away, but the trade-off was they were able to watch themselves ejaculate. I'm always mesmerised by that, and it was so hot watching them shoot off one by one like little fireworks.

But I wondered when I'd be able to see that again. I'd wanted us to carry on masturbating together over summer with anyone who was up for it, but everybody I'd asked either didn't want to, or said they wouldn't have time.

After my third orgasm, I was distracted by an unfamiliar moan. I looked over to see Maria, one hand furiously rubbing her clit, the other holding her nipple firmly, and her eyes tight shut as she finally got herself off. We all gave her a little round of applause. She looked a little embarrassed when she opened her eyes, but she was trying to hold back a giggle.

I could easily have given myself a fourth orgasm, but I decided to stop there and get dressed. Just before I left the changing room, I spotted some semen that hadn't been cleaned up. I then realised it was in exactly the spot where Thomas had been sitting. Good for him; I hope he enjoyed himself.

I then saw two of the other boys just outside the door. They asked if they could have a word with me, and took me into what was supposed to be the boys' changing room, which didn't smell as bad as I'd heard it did.

I didn't know their names at that point, but they always sat next to each other and I would spot little knowing smiles between them. The taller one said, 'We heard you wanted to keep wanking over summer, or whatever girls call it. Why didn't you ask us?'

'Oh,' I said. Wow, I didn't even think of asking them. 'I, er... I didn't think you'd be interested.'

'We're not gay,' they said quickly, seemingly catching on to what I meant. 'We like girls.'

We spoke for a few minutes. I found out the taller and chattier one was called Steven, and the quieter one was Jack. They told us that every weekend, Jack's sister let them use her flat when she went out with her friends, so we could go there. I felt myself growing wetter and wetter the more they talked, since I'd never talked about sexual things with boys before. But I thought of one person who would make it more special.

'Can I ask Tiff as well?' She'd already said she was more interested in having sex with boys than masturbating with them, but she was my best friend and I had to offer her the chance.

Steven and Jack gave each other one of their smiles. 'Yes, of course, you can.'

Tiff was just leaving the changing block, so I caught her outside. A couple of teachers were around, so I whispered that I had something exciting to tell her when we were next alone.