Love to see a dude's balls right through the clothes he has on.
A dude who's helpless (I have him pinned or tied up), and I get to bust his balls and see that special look on his face.
The look on a guy's face and his body reaction after a hit in the balls or while being kept right on the edge
My own nuts played with
Nice abs, even more if exposed
Firm pecs

My nuts being busted too hard
Permanent damage
lots of body hair
flabby belly or pecs