Warning: my rants are mean, petty, and bitter. If you can't get into that, don't look behind the cut.
Lave. Is there some kind of rule that says every third story must feature laving? It's a good word, people, a fine word, but it's become a trifle overused, in the same way that, say, Los Angeles freeways are a trifle overcrowded. It's OK to use "lick" occasionally. You won't be expelled from Fangirlia or anything.
Weeping Cock. I mean, yes, fine, if you must, but some stories contain so much cock-weeping that I find myself wanting to put the cock on suicide watch and search it for sharp implements. And the associations with "weep" aren't good. Sores weep. The heroines of three-volume Victorian novels weep. Cocks, especially ones engaging in sexual activity, should probably keep their weeping to a minimum.
Arching. This is a fine word that nicely conveys a common body movement during sex, and I certainly wouldn't want writers to stop using it altogether. But overuse of it leaves every story sounding like a manual for aqueduct manufacture and every character sounding like a patient with tetanus.
Pale Cock. Cocks are not pale, especially not in a sexual situation, so this phrase should not occur in fan fiction nearly as much as it does. The only time I can really see that phrase being useful is maybe, maybe, in the aftermath of an Anne Rice-type vampire attack, and even then it's probably - no, make that certainly - better not to go there.
Wailing, Howling, Shrieking et al. Words like this fit in the category of "We know what you mean, but we wish you would come up with a better way to describe it." I don't associate wailing, howling, and shrieking with ecstasy; I associate them with werewolf attacks. (This, of course, is not a problem for those fandoms in which sex and werewolf attacks are almost indistinguishable from each other.) Yes, anguished noises are a necessary and wonderful part of sex, but if my sex partner started wailing I would not construe this as a positive comment on my sexual prowess. It consistently surprises me that I'm invited to see it that way in fan fiction.
Nasty. I find this one annoying when it's used as a positive adjective when describing sexual activity, particuarly kissing. I know it's a slang term. I know descriptive words tend to acquire opposite meanings in colloquial usage. Doesn't change the fact that my first thought, upon reading this term, is of garbage left out overnight in the summer, and my second thought is of Janet Jackson. Neither of these images should ever be remotely connected with sex, and no human being should be forced to consider sex, garbage, and Janet Jackson all at the same time.
Male Sex when used to mean "gay sex." One does not have male sex. One is of the male sex (or one is not). And there is no reason at all to invent a new term for men having sex with men, not when we already have so many at our disposal.