Yes. A few times because the timing or place was was wrong. But more significantly, and the time I'll never forget, is when a really good guy friend and I were together in his office for some reason and had been drinking. A little too much drinking. He is (still is) a very special and very wonderful friend. I've always wondered what sex with him would be like, but knew in the back of my mind that it might wreck the friendship. So we had never crossed more than an occasional flirty line.
But the night in question, flirting happened and then we all have experienced it - that deep longing look into someones eyes and BANG, you kissing them. Almost everyone I know has had it happen, even married people to non-spouses. Anyway - he and I kissed, his hands wandered under my blouse and felt so nice as he took my tits in hand and opened my blouse. Like an automaton, I had him unzipped, cock out and in my hand.... then a moment of "oh shit ... we have to stop..." It was tough, but we did stop. His cock is lovely, and I'll never forget that I held it in my hand ... but if we were going to remain friends, I had to turn it down. He had this pleading look in his eyes, and I suppose he was willing to cross the line -- but we stopped it, and are still good friends, but now we have an amusing story to tell ourselves.
I did feel sorry for him, though - and I encouraged him and watched him jerk off from the other side of the couch. At least I got to see him "in action".
Still the best of friends, and non-lovers, although with a hint of intimacy... "Remember that night you held my boobs and I watched you jerk off".... Interesting and still just friends with a slightly intimate story to tell.
one where I regretted?
the one I most regret was way back in college. my physics prof.
he was married, 40, your typical college prof, graying beard.
we'd have lunch together, and we really connected, that familiar mutual sexual attraction was overflowing.
I really wanted to, go into his office and immediately start taking my clothes off.
wish I had. I'd never done a guy that old haha.