My relationship with Cheryl had just about run its course.

Cheryl was a bleach blonde, medium height, pretty face, brown eyes, and a few extra pounds which she carried well, but her two most standout features were her large all-natural breasts and her magnificent bubble-butt.

My problem was that Cheryl was such a control freak. Okay, that had its good points. We always got top-notch service in restaurants, although the way she chewed out sub-standard waiters made me cringe many times. But it was the way she extended her control into our relationship that was becoming more and more irritating. Her only weakness was her fondness for getting mildly tipsy.

Cheryl still lived with her parents most of the time, but stayed overnight at my place occasionally. She preferred to be the one who initiated sex, and usually that was with her on top, occasionally in the missionary position. She wouldn't let me fuck her doggy-style, and she definitely wouldn't let me fuck her in the ass. What an absolute waste of such a magnificent asset!

I knew from experience that Cheryl didn't like her breasts to be mauled. They bruised easily and would feel sore for days afterwards. However she really loved having her nipples tortured, and one night, after having a bit too much to drink, she confessed that she secretly pleasured herself at home using nipple clamps with five pound weights attached with cords, and dangling over the banisters so that the weights could swing freely like pendulums while she jilled herself. Obviously she only did that when her parents were out!

I don't want to make out that our relationship was bad; Cheryl and I had a lot of good times together. But I had come to realise that she was not a woman I would want to spend the rest of my life with, and it made sense to end it sooner rather than later.

I live on the top floor of a converted four-storey Victorian town house. There were two self-contained flats on each floor. I lived on the top floor, and my neighbour was a nice elderly lady named Mrs. Ross. The building had been converted before lifts were commonplace, and soon afterwards it had been made a listed building, so although there was plenty of space to install a lift, preservation of the original Victorian staircase took priority. One of the reasons I took the flat was that the rent was cheap because of the lack of a lift, but I was not popular when I had a washing machine delivered and the delivery men had to haul it up all those stairs.

The stairway was strange and space-inefficient. It took out a large oblong bite from each floor. Doors to the flats were opposite each other on the short edges. The steps upwards were on one of the long edges, fronting the building so you could look out as you climbed the stairs. That meant there was quite a long flat length on each floor which apparently served no purpose. If you leaned out over the handrail on the flat part, at full stretch you could grasp the stanchions supporting the handrail on the ascending stairs. (Although I lived on the top floor, the stairs continued up the roof. The roof was forbidden to residents, and the door was kept solidly padlocked.)

My opportunity to end the relationship with a bang was presented by Mrs. Ross going to stay with her sister for a week (and asking me to look after her cat) coinciding with Cheryl's birthday. Cheryl's parents took precedence for her actual birthday, but I arranged to take her out for a nice meal the evening before, and she agreed in advance to stay the night with me so she could have a drink.

I didn't skimp on the meal. After all it was my dinner as well. I gave Cheryl her present while we were in the restaurant, and that I had skimped on. It was some cheap jewelry knick-knack. I could tell she was trying to hide her disappointment, but her eyes lit up when I told her I had a special present to give to her later.

Cheryl drank too much, until she was nicely tipsy, whereas I took only tiny sips so that I was still virtually stone cold sober. I had to help Cheryl up the stairs to my flat, but when we got there I cracked open a nice bottle of wine to keep her merry.

When we retired to bed, Cheryl got on top and rode herself to a nice orgasm. I didn't let myself cum but Cheryl didn't notice, she just rolled off me and went to sleep.

I waited till after midnight and it was actually Cheryl's birthday. She was sound asleep and snoring softly. I went out onto the landing outside my flat and removed all the lightbulbs from the stairs from the floor below upwards. That way I reckoned only someone who knew what they were looking for would notice what we were about to do because we'd be cloaked in darkness.

Cheryl was still sound asleep when I returned to the bedroom with my supplies. Round each wrist I knotted some stout cord, which I then tied round her thighs. I wanted to keep her hands restrained, but be able to release them one at a time. I then tied a thick blindfold round her eyes. Cheryl started to wake up when I inserted the ball gag but it was too late, I had her under control.

She tried to struggle, emitting weird humming noises of protest through the ball gag, but I told her to relax, that this was her special present and she was going to enjoy it. After a few minutes she seemed to realise that her protests were to no avail. I got her out of bed and led her, still naked, onto the landing opposite the stairs. I forced her ankles wide apart and tied them securely to the stanchions supporting the handrail.

I unfastened the cord around one of Cheryl's thighs, gently kissing the red track marks it left behind. Then I went round to the stairs on the opposite side and pulled. Cheryl panicked and started to struggle again when she found herself being bent at the hips over the handrail, but pretty soon I had her upper body stretched out horizontal with both wrists secured to stanchions on the stairs, her sumptuous breasts dangling down over empty space.

Next I attached nipple clamps, and added two pound weights with enough cord that they could swing freely below. I knew she was used to five pound weights, but the best was yet to come.

I had remembered a science prog, where they had demonstrated the action of a pendulum. All very straightforward and predictable. However then they added another pendulum attached below the first and set the pair in motion. The result was crazy, the motion so chaotic that predicting it was way beyond the capabilities of home computers of the time.

On each two pound weight pendulum attached to Cheryl's nipple clamps, I hung a five pound weight pendulum. Then I started them in motion, watching Cheryl as the weights bucked and kicked unpredictably beneath her. The effect was electrifying. She was soon moaning and squirming with pleasure, her glistening cunt lips betraying her arousal.

Suddenly Cheryl moaned so loudly I was worried the people on the floors below might hear, then her whole body seemed to freeze rigid. I saw familiar rippling along her stomach and a reddish blush on her chest and I realised she had orgasmed solely from my double pendulum nipple torture.

Now it was my turn for some fun. I prefer my ass-fucking bareback but obviously Cheryl wasn't properly prepared for it so I incarcerated my turgid member in a rubber jacket. When I drizzled some lube down her butt crack and massaged it into her little brown virgin portal, Cheryl realised my intentions and started to struggle. Her motions agitated the double pendulums, causing them to torment her nipples chaotically.