Because Monsieur Roget neglected to include some of the risqué words we writers of erotica need, I've compiled my own short list of synonyms. I hope it is of use to you in your quest to pen tales of literary titillation. (Try and say that ten times fast!)
Please note that not all these synonyms are interchangeable. Neither will any synonym necessarily fit the tone of the scene you're writing. A good writer will take into account the proper usage of a word and its nuances of meaning.
balls – ballocks, bollocks, crown/family jewels, gonads, nads, nards, rocks, nuts, scrotum, testicles
cock – bone, boner, dick, erection, genitals, hard-on, hose, lance, manhood, meat, member, organ, pecker, penis, phallus, pole, prick, rod, root, sex, shaft, staff, stem, tool, wood
glans – bulb, crown, head, helmet, knob, mushroom tip, tip
clitoris – bud, bump, bundle of nerves, button, nub, nubbin, pearl
lips – creases, folds, labia, nether lips
nipples – areola, buds, peaks, tips
pussy – beaver, box, bush, cleft, crease, crevice, crotch, cunny, cunt, fuckhole, gash, genitals, glove, hole, mound, muff, opening, quim, slit, snatch, twat, vagina, vulva
tits – boobs, bosom, breasts, chest, dugs, globes, knockers, mammaries, mounds, rack
ass – arse, backside, behind, bottom, bum, buns, butt, buttocks, cheeks, rear, rear end, rump, seat
come (noun) – cream, cum, ejaculate, honey, jism, jizz, juice, secretions, seed, semen, spunk
come (verb) – blow, climax, cream, cum, ejaculate, get off, jet, peak, spend, spray, spurt, squirt
I'm open to additions, so if you find any synonyms that I've forgotten, please feel free to email them to me so I can add them. That way we can all benefit. :) Also, I'm human, so votes and feedback are valued. Thanks!