Seeds of the Rainbow

This book, first published in '57 as no. 45 in the Traveller's Companion series, is among the toughest works to find. (No. 44 was a little something called The Story of O, a title that initiated yet another French government crackdown on Olympia, perhaps explaining Rainbow's scarcity.) Seeds of the Rainbow is the tale of Sid, a man as gifted in the priapic arts as he is lacking in physical beauty.
Not without his charms, he still finds himself behaving aggressively towards the women in his life. Extremely aggressively. Thankfully, a baby comes along that lets Brenda, one of several objects of Sid's desires, sacrifice her chaste nature (even after they'd been together), and really go for it with Sid. Too bad for her, there's no real going back from Sid, certainly not to a doctor fiance who won't even give a girl a proper kiss.
Nicely done by Desmond, and containing other incidents too numerous to list.