David and Margaret had known each other since childhood. They had been in the same class at primary school, and at secondary school. Margaret had always been brighter than David, regularly being top of the class while David was just about average, somewhere in the middle.
So when it came to the GCSEs it was no surprise that Margaret got top grade in all of them whereas David's grades were only so-so.
Then they went on to A Levels. This was also when their sexuality began to develop. Nearly all the girls there started to have boyfriends, but not Margaret. She put it about that she wanted to concentrate on her A Levels first to get top grades and then go on to Cambridge University to read Law. This was only half the truth, the other half being that she was not that turned on by males and wondered if she might be lesbian. She honestly was not sure.
David on the other hand had no such inhibitions. By the time he sat his A Levels he'd had sex with at least four girls and had the virginity off three of them. But he really wanted Margaret. That they were the same age didn't matter to him. He looked up to her partly due to looks but also because he envied her always being top of the class. And when he asked her she didn't exactly turn him down, just said: "Wait till after our A Levels. Ask me again then."
And so he did. The day after his last A Level he asked Margaret out for a coffee.
"You're on." said Margaret. "Nando's Saturday at three o'clock?"
"See you then."
And so they met up. But it was Margaret not David who took the lead.
"Look, she said "I know what's in your mind. But before we come to this I think we should first be honest with each other."
"No problem"
"Well first, I know you've been having sex with other girls. One of them, Felicity, is a good friend of mine. But for me, with you it would be my first time. At eighteen, would you believe? But it would also be special. A girl's first time usually is."
"I am honoured Margaret"
"Second, I am not entirely sure I am wholly heterosexual. I've not had such a relationship with a girl either yet, though I want to do so soon so as to find out. Do you have a problem with that?"
"No, none at all. Though I'm not gay: I'm sure of it"
"Fine. Third, I'd want a guarantee you couldn't be two-timing me like you did Felicity. Don't say you didn't. I know. And Felicity was very upset."
"What can I say?"
"Nothing. Because of what you did to her your word alone won't be good enough. I'd want security and a guarantee."
"How?"
"Chastity device and I control the keys for as long as we're an item. It's June now. Uni term starts October. So till then."
David was quite taken aback. He'd suspected Margaret was still virgin, even considered she might be lesbian, but this one he'd not seen coming at all.
"Are you serious? I've not got one and have never heard of them. I want to think about this. Where do I get one?"
"Don't you worry about that. If you agree, I shall get one for you. I'll even pay for it. I can get it in two or three weeks if I know your size. So one thing at a time. I've never seen you naked nor you me. We can remedy that first and shake hands on it. And it'll probably only be for four months as we are both looking to go to different Universities. Deal?"
"Deal."
"I knew you would. You showed all the signs of someone who wanted to experience control by a Dominant woman."
"That's true too. How did you know?"
"I've an intuition for these things. Trust me."
And so it was done. And the device she got him wasn't a cheap plastic one either. It was a titanium alloy maximum security pretty much impossible to remove without the key. She'd done her research. And made to measure: she'd made sure of that so he could wear 24/7 with no problems. But she was good as her word. They had sex regularly for the next four months. And David enjoyed it far more than he had with other girls. And he was surprised to find that the feeling of being locked was a turn-on for him. Holding his keys was definitely a turn-on for Margaret.
Meanwhile the A Level results came out. She'd got top grades with distinction in all subjects and won her place in Cambridge. Though David had just missed out:no more academe for him as he'd need to be out in the real world looking for a job to earn his living.
Shortly before she was leaving for Cambridge she met with David again for a coffee at Nando's.