I've written here before about how much I love to see a nice big dollop of precum (technically called Cowper's fluid) oozing out of a man's cock. Unfortunately, in porn, you don't often see precum.
I am quite a leaky lad myself, and during extended foreplay, I can get pretty drenched. One of my favorite things in the world is when my lover rubs the precum around on the sensitive glans of my rigid cock. This can be one of those ecstatic agony moment, where it's heavenly torture, particularly if he already tied up my hands so I can't stop him from edging me. Precum takes a long time to dry, so he'll stop for a moment until he's certain I won't shoot, then he goes right back to torturing me.
These great shots came from the excellent blog Beef, Boots and Buttplugs.