My Penis ... I pay with it often enough :wink: :kitteh: :tongue:
( :shocked: I meant to type "play", but I find the concept of paying with one, like going to the supermarket and swiping it in the debit card thing amusing, so I'm not going to change it)
Hmmm, on a more serious note, talking just about external body parts (and any other essential body part for life because there are a few vital ones that you need in order to live in there and I have a hard time choosing between them :tongue: ), I'm gonna go with my eyes, because sight is so integral to daily life and how I enjoy it (sight makes it easy to enjoy a landscape) :crazy:
As far as appearance, I don't think I have a favorite. I just like that my partners have liked my body parts. That said, I do have a few spots where I enjoy being touched the most :wink: But I don't have a feature where I'm like' "I'm gonna show them this, because it is my good side", except for my penis after I trust someone enough and feel close enough to them to show them it (and after they already saw it before and told me they liked it :tongue: because it is easy to be a little nervous the first time).
Edit: I also like my arms, 'cause they are used for snuggling :kitteh:
the part that isn't my body... the stuff that goes in and flows out... the energy, things like that. Otherwise it's my arms, hands, and legs; my legs let me move from place to place, and my hands are the instruments of action.