Sexual freedom seems pretty common in Randland, doesn't it? The Domani women are known for their open-minded attitudes, the Aiel have a very pragmatic view about nudity and seem not to frown on casual sex either (Aviendha clearly had no hang ups about sleeping with Rand, while the latter was suggesting marriage) and so on. With heartleaf tea apparently doing the job of birth control, there's even less reason to limit people's libidos. The 2Rivers were of course puritanical, but it's a small village so who can blame them. The apparent lack of prostitution seems a bit odd, though, doesn't it? The only example I can think of are the Altaran male escorts pampered by society women, like Tylin did with Mat.
Among the main characters, everyone is almost alarmingly chaste! Elayne had one moment of drunken flirting with a man before her relationship with Rand. Egwene had Galad. Perrin had Faile. The only one with any experience was Mat. Personally, I don't have a clue how much even he got it on. Was his 'kissing and cuddling' random barmaids suggestive of something else or was it just Melindhra and Tylin before Tuon?
Writing-wise, I think RJ's sex scenes were pretty good. Very non-smutty, implying but never revealing (or revelling) much. And just like his prose in general, it was functional - not beautiful or profound, but you get what's happening. Although perhaps he had one good moment - Rand's shame and self-hatred after he had 'raped' Min was well done (the reader must have been as mystified as Min about what Rand's problem was!). I never understood that scene until I slept with my ex-bf with whom we acted out the exactly same scene, me as mystified, angry and amused as Min.