Back in college my roommate and I regularly masturbated each other. It started late one night when we went to take a shower. No one else was in the shower at that hour and my roommate followed me into the same stall. We got to horsing around, one thing led to another, and we ended up masturbating each other to climax.
That first time everything flowed so naturally and felt so good that I didn't think about the implications. Afterwards I felt guilty. I'd never done anything like that before. But I didn't put up any resistance when my roommate crawled in bed with me a few nights later, and we went at it again.
After that, our sessions became routine and I stopped feeling guilty. For the first month or so we masturbated each other almost every night, but as time wore on we settled down to two or three times a week. (Of course we were masturbating separately the rest of the time.) Our first encounter in the shower happened when we were sophomores and we kept at it until we graduated.
At first it was awkward because we're both right-handed and we had to do a lot of squirming around. Over time we refined our technique. Eventually, we figured out how to do it face to face with one guy lying on his back while the other got on all fours between the bottom guy's legs. The guy on the bottom would do the stroking, holding both of our cocks together in both hands. The guy on top could hump the other guy's hands with his cock in them. With plenty of lube it actually felt sort of like fucking a vagina. That was one way, but we did plenty of other stuff, too.
We never kissed, we never had oral sex and we never penetrated each other anally. I think we stuck to those unwritten rules because we could tell ourselves it was all just a release and we weren't really doing anything homosexual. It took me a long time to admit to myself that I was physically attracted to my roommate, who was (and still is) good-looking and athletic. And the attraction was obviously mutual.
After our first encounter in the shower, we were much more careful about where and when we did it. We weren't too eager to have the guys we hung around with find out what went on in our room after the lights went out. And as far as I know they never did.
After we graduated we went our separate ways. We still keep in touch but we haven't done anything with each other for years. In fact, since college I've never had man-to-man sex again. But I still go back to those college memories when I'm masturbating and especially that first time in the shower.