I usually have no desire to look at other guy's cocks, but years ago in college I was showering at the sports facility after a swim in a large, men's open shower and couldn't help noticing a guy next to me.
He looked to have a bit larger than average penis (judging from flaccid size) but a very pronounced glans with a big flare out and over the coronal sulcus around 2/3 of the circumference. Not only could I not help looking at him, I couldn't help thinking that it must be great to be a woman feeling that thing slide up and down inside of her.