Hmm I'm gonna leave size out of it because I like all sizes so I'll try my best.

The perfect cock has prominent veins along at least two sides of it, doesn't matter which sides. The veins affect the profile of the dick and make it look distinct and visually interesting. A fat mushroom shaped head is also wonderful if it's slightly big enough to look disproportionate to the shaft even better, they're just more fun to suck on that way. (that's probably not realistic tho).

I've no real preference for the direction of a dick's curve but I do like when they have one.

I don't care if it's circumsized or not. Though I do wish every man on earth who is circumsized had been given the choice barring some major medical issue when they were infants.