Besides the obvious body parts, I have a more than slight appreciation for the male nipple.
Just like snowflakes no pair of them is totally identical to another. Some have rounded flat knobs in the middle while others' knobs are more pointy. Some are otherwise flat, some have more little "bumps" - usually hair follicles, functioning or not. Compared to coins they can range in size from a dime to a dollar. While many are placed smack-dab in the middle of their host pecs there are some (especially when the muscles are, ahem, overdeveloped) that are located lower. On lighter-skinned guys their coloration can be anywhere on a continuum from pale pink to dark brown, otherwise there's still a spectrum although narrower (shades of pink/red/tan don't apply.)
In typical youthful eagerness to "cut to the chase" I neglected nipples while goin' at it, at first, until one epic hookup when all that changed. Instead of diving directly from his mouth to south-of-the-navel territory with my mouth, I decided to give a quick lickin' to the engorged knob of his left nipple. (The engorged knob farther south got attention soon enough.
) His heavy breathing immediately changed to short deep gasps. So then I worked that knob between my upper and lower front teeth and - CHOMP!
My hookup partner reacted like an electrical charge had gone through the mattress he'd lain on his back on. His entire body jolted and arced, while his "manhood" stiffened and then jumped like a dolphin.
"DAAAAAAMMMMMMN!," I thought! From that day on I added nipple nibbling to my bag of tricks.
Few things seem to better guarantee a soft-to-hard or hard-to-harder shift of penile gears. Knowing this, when scoping a guy's body I definitely focus on the "T" as well as the "A" and what's in the basket.