I've seen a lot of my mates' cocks. Being nearly 6' 6" it means that at pub urinals, if we stand next to each other, my periphal vision always gives me a clear view of the goods! When you've had a few beers, in any case, inhibitions are lowered and you tend not to be so paranoid about standing close to the troughs or pans.
A couple of them I've had a wank with a few times. I've always enjoyed that, it seems a bonding thing to do, a closeness that none of your other friends may have with you. I've no desire for such events to go any further but I do wish my current circle of friends had a few more less-uptight individuals in it who were cool about sharing the moment with a good mate!
I've got one current mate of over 20 years who discusses the most intimate details of his sex life (both with his string of girlfriends and 'solo') - even in the middle of the pub, who's completely uninhibited when it comes to verbal exchanges (even I've been embarrassed at some of the conversations in pubs, in case people on the adjacent tables are listinening!). I've suggested a few times that we should hook up and watch some porn and just kick back and wank together, especially as he's circumcised and I'm not, but he just doesn't seem up for it. He's one who's even too shy to pee together, yet describes to me every intimate detail of his tool. I think that he's just a prick-tease.