[JohnSmithJones]

This observation was brief, but quite a turn on. When I was a graduate student, I lived in the first year in a fairly crummy student hall as it was all I could get at the time. The walls weren't paper-thin but they weren't all that thick. You can't expect much more in a place like that.

My next door neighbour changed in the middle of the year and a slim, innocent-looking young male student moved in. We got on well enough but were not close.

A couple of times, I was there when his girlfriend came to visit him. They were an interesting couple. He was tall and slim, she was short and very curvy. The first time I saw her, her big breasts bounced a little under her top. From the back of her top, I could just make out she was wearing a lacy bra as I could see the texture of the lace. I liked that - a slightly geeky girl without the best fashion sense, but who likes to wear bras that are "pretty" and feminine.

Anyway, this only happened once - but one time, the girlfriend had come to visit and was in the guy's room. This was the middle of the afternoon, and I was in my room answering some emails.

At first I only heard vague noises from next door and thought nothing of it. Then, suddenly, I heard the girlfriend's voice beginning to moan. Instantly I realised they were having sex - being quiet at first, but she was obviously the type of woman who cums very vocally, and just cannot control herself when she gets close.

I heard. "Ohhh... OHHH! OHHHH! OOOOOH!" I could hear her voice quite clearly - obviously her orgasm was building up, but not quite there yet. I immediately began to get hard, imagining her naked with those big tits bouncing as they fucked.

"AAAAH.... AAAAH... AAAAAAH! AAAAH!" Her voice was rising in pitch now and getting faster. This had to be it - she was just about to cum - and sure enough she let out a loud satisfied moan with what was obviously her orgasm.

"AAAAAAAaaaaaaaaah..." I couldn't hear anything clearly after that.

At that point I was as hard as a rock - I couldn't resist a wank, and jerked off. I didn't last long, I was pretty turned on.

Sadly I never once heard them having sex again, I was obviously not there at the right time. But it was hot knowing that the girl was so utterly unable to control her moaning when she came.