Possibly strangely, I've had many more in depth conversations about my cock and my mates' cocks with some of my straight mates than I have with gay or bi friends!
I've had really detailed conversations with one of my mates (he's circumcised) about our cocks: length, girth, his circumcision, my foreskin, our wanking habits, experiences etc. - usually at his instigation rather than mine, although we've never actually got our cocks out and compared them or techniques - just chatted about it. A shame really, I've always wanted us to whip them out and have a good wank together, I think it's a great bond to see a close friend at his most vulnerable and ejaculating, but it's a step too far for him.