I was in bed, getting ready to go to sleep. Since I wasn't really tired, the best way for me to get to sleep was to masterbate, and just feel the pleasure as I fall asleep. So I was masterbating in my bed, almost ready to cum, when my roommate comes in to go to sleep. I had to stop, and I was just laying in bed so hard and horny, and now I'll have to wait a while to make sure he's asleep before I try again.
This happens more than it should. I have to wait till I'm tired enough, so masterbating will get me to sleep, but by then my roommate decides he wants to sleep too. I really can't wait till april when I get my own room finally.
