Well ok but the bladder isn't as good as it used to be so we'd probably have to stop for a break ,or else you going to get mighty wet !! Problem??
Personally, I think it would be the entire penis!!! I do have to add that I don't find all penises sexy or visually appealing. There is a very specific size, shape and appearance that I find sexy and arousing. Like anything, there are beautiful works of art and there are ugly, unappealing ones!!
The first cock I held was my friends. It was meaty and veiny with a big rubbery foreskin that covered the whole cock like a big rubber sheath. So it was the veininess of the shaft as the foreskin moved over it. With sucking, it's the tip absolutely.
I love every part of the penis: the head, the shaft, the pee hole. If I had to choose, I think the head would be my favorite. Wonderful shape and texture.
The part in her mouth lol. But seriously, my two friends both like the head but, of course, it's no good without a stout shaft to deliver the rest.
Cum slit ! Love to watch as i slip a silicone sound between my slit lips and stretch them apart ! Also love to watch cum as it oozes out of my slit !
My wife says she likes the way the round head fits unto the roof of her mouth. That way when she's ready to finish me, she can slide her tongue on the frenulum and I'll be ready to deliver in ten seconds. Oh, that tongue! On one late night nurses talk session, as the token male, I got asked why we like oral sex so much. I said one reason is that your vaginas don't have a little wiggling thing moving around inside them. I've always wondered if some husbands or boyfriends began getting special treats after that.
My favourite part is my head…. I need to learn to stay away from it when I masturbate to last longer.