It's an odd thing that we can feel so inhibited when we see a friend's equipment and want to comment on it but fear of retribution is so high. Luckily, I went swimming with a good work colleague a few years ago and we had to share a changing cubicle. I just commented on his long foreskin and he was happy to demonstrate pulling it back to expose his helmet. His comments were on size of my bollocks. It was funny and horny in a bonding kind of way. Meant that we had taken a first step and when we were drinking a couple of weeks later at a stay over work seminar, it was not difficult to end up back in his room, naked and wanking to porn. Often repeated since with no strings. But it still feels like jumping off a cliff to make the first comment..

I have told several friends they have a nice cock. I am smaller than all of my friends so they all look nice to me.

Was easier for me as it started as a joke with a couple of friends early on , but I agree much later on it can be hard to say without it looking as if you are hitting on them. Which you may want to do but if it goes wrong, you cannot rewind..

I had a roommate in college I would joke with about this. If he asked me what I was doing that night, I would say "I'm going over to slip Cindy (my gf) six inches. He'd usually say something like "that all?" or "Let me know if she needs more". One day I walked in on him as he was exiting the shower and he was sporting at least 8" soft. Absolutely huge cock. I gasped when i saw it - said "holy shit". He smiled and just said "yeah I've got a rope". After that I didn't make any more 6" jokes...