I prefer mine with a little curve upwards. And circ'ed. (sorry to the 'in tact' guys... it's just my personal preference).
Hair trimmed to an inch or so, but not shaved off (because guys won't keep up with it, and then I'll get scratched with stubble).
Freshly cleaned. Not that I don't like the musky smell of a man that has been sweating... but it can get pretty rank in an area that's been closed up all day. And if I'm doing you the favor of putting my face down there, the least you can do is wash the area.
Thick, but not too thick. Long but not too long. I still need to be able to wrap my hands and mouth around it, and I like it if the dick is not too long so that I can take it all in during a blow job.
Attached to someone tall with wide shoulders. I'm defintely a shoulders girl.