Anytime I have a shower in the locker room, I always slide my skin back and wash the head, dont care who watches, most guys never pay any attention, I have seen a few guys watch, If I notice anyone watching, I usually show off a little, slide the skin back and wash the head good, then slide it back and fourth a few times, and soap it up good, I've come close to popping a bone a few times.
A while back I noticed a young guy at the gym, around 18-20, he usually had a shower the same time I did, not anything weird, we were just there at the same time, he was uncut too, I noticed as we were drying off, as soon as I slid my skin back to dry off the head, he would do the same thing at the same time, every time, I know he was watching, and i did think it was strange he would slide his skin back and dry the head at the exact same time I did. we never talked or anything, just dried our dicks and left.