While this happened almost 30 years ago, it's still one of my favorite mastubatory fantasies.
My roommate Chad was a great looking guy, blonde hair, could pass for a surfer but we were up in the Mid-West. He was an avid skier and hockey player. He was also quite successful with the ladies. There was more than one night when I would lay awake listening to his lovemaking. Frequently when we were alone we would lay in bed and have deep conversations about life.
Finally I worked up the courage to ask him one night if he would be interested in getting a massage from me. My heart was pounding as he seemed puzzled by the question and then after what seemed like an eternity, he whispered 'sure'. I was in my underwear and I walked over to his bed with a raging hard on, hoping he wouldn't notice. I then began one of the most satisfying, hottest sexual experiences I have ever had. As I massaged his neck and shoulders, I began to slowly work my way down his back towards his beautiful tight ass. With each move downward I would peel back more and more of his bikini briefs, exposing this incredible ass. By this time my heart was pounding so hard I thought it would jump out of my chest! Eventually I slipped the briefs down his hairy legs and completely off. So there was my roommate who I had fantasized about all year, laying in his bed naked! I worked my hands up his legs and into the warmness of his balls and he arched his back to allow me more room to play with his rock hard cock. Slowly, he turned over and I went to work stroking him off. He laid there groaning with pleasure until his hips began bucking back and forth and he shot his cum all over his chest and my hand.
I went back to my bed and slipped out of my briefs and stroked myself to the most amazing orgasm I think I ever had. I looked over while I was in my throes of ecstacy and saw that Chad was laying there watching my every stroke.
We had a few more encounters that semester and I transferred to another school and never saw Chad again. But even to this day, I get hard just thinking about the fun we had together!