Gulliver's Travels is fairly raunchy, in that there are lots of booby jokes. It's also fairly prudish, in the sense that Gulliver spends a lot of time scolding women for being seductive and wanting to have affairs (about which, check out our theme on "Gender").
Gulliver's sexual feeling wanes throughout the whole book as his hatred of humans takes over. In the fourth part, once he has been thoroughly converted by the Houyhnhnms, Gulliver screams when a randy young Yahoo embraces him as he is swimming. And once he returns home to England to stay, he can't stand to smell or look at his wife. He is reminded that he once had sex with a Yahoo and made even more Yahoos. So, actually, we would have to say that, for such a frank book, Gulliver is surprisingly squeamish about sex – it's there, but it's definitely not steamy.