Spock's Genitals in the First Times series, aka The Spocknads

 

Some people have asked questions about it in a mailing list, so here is a description of them. Yes, I'm plagiarizing myself again from those posts.

The male Vulcan genitalia appear just before their first pon farr, when hormones wreak havoc in their systems. It starts growing then, before that their bodies are not sexually mature. (It's better detailed it the first First Times story, go read it already ;-)

Under the skin is a pouch. When your average Vulcan specimen is aroused, blood fills a little something in there which then peeks out (think: vagina + the inner mouth in Alien) (yes, I'm proud of that slighlty vagina dentata image)... which means there must be a much bigger difference between erect/flaccid penis in Vulcans than in Humans.
It retracts relatively quickly after orgasm, and is functional again soon after.
Males have some control over their arousal, to a certain point.

I tend to see it as slightly translucid (and greenish, of course), with a very fine, sensitive skin, since it's usually inside & therefore protected, like most human mucous membranes, and somewhat slicked, too, for the same reason. Males need lubrication to get it out... and in. Wherever 'in' is.

No head / shaft thing, too. Just a proud, towering pillar of green, veined marble rising from its nest of black curls like the column of a Greek temple devoted to Aphrodite ;-)

No cut/uncut!

And, I love frals. I couldn't NOT use frals.
There are normally two of them, and are supposed to wrap around the cock and get inside the female's vagina, and wave around to help sperm along. Yes, it's silly, but I needed an explanation for their existence & I had this image of frals waving and tickling Jim's belly. (I know, I didn't use it - yet).
Spock has an extra, smaller one. A little change from the norm, like people who are born with six fingers.

Frals are the reason why Kirk uses squeezing rather than stroking on Spock. Since they wrap around Spock's cock (and what is around said cock), you can't use vigorous friction, it would just tear them off, especially since the skin of the whole thing is pretty thin and delicate.

Also, Vulcans do not produce sperm outside of pon farr, usually – but it can happen, when they're really, really, you know, excited. And they don't pee, officially because they're a desert species, officiously because I just can't do, or write (and hardly read) fellatio at the slightest hint of the possibility of pee, and I thought: 'no pee, more blow-jobs. Let's have a better-sounding reason for that now' ;-b
The desert thing also conveniently explains that genitals are usually inside the body (where moisture is kept) and the quick retraction after orgasm. No need to have it hanging out all moist, where it would catch every grain of sand in the vicinity.

And the name 'spocknads' comes from Farfalla! (check out the recs for her websites)

If you have more questions, feel free to ask!