Most notable that I can think of is my friend, let's call him "g," who stayed at my place when he visited the town I live in a few years ago. I should preface by saying we used to be lifeguards together and I had seen him nude once in the locker room. he is super cool and open, and a good-looking dude I'd say. Anyhow, I'd seen his dick after the pool one day and noticed he was uncut too.
Then, while visiting me, I woke up late one night with a boner and had to pee. I was standing at the toilet waiting for it to go down and he accidentally walked in. it turned me on a lot, to be honest. he pretended he didn't see but i knew he did. he was super apologetic and almost ashamed. i told him it was cool, but he shoulda bought me a drink first. after that we were a lot less modest with each other. i also think that now he knows that i'm hung he started seeing me differently.