Nothing sixual, only flirtatious at best. I do remember in Morrowind a certain tavern where girls were dancing in their undies (the House of Earthly Delights, thank you MudCrabFever), but that's the most I've ever encountered in the TES games.
well there is one misc quest this is a very minor spolier: Spoiler in Markarth where the Jarl needs a stallion potion delivered to him and the quest giver says 'this potion should help his problem in the Bedroom'
I know its nothing major but it's a reference that was pretty funny, who knew TES had its own version viagra. Eh, I didn't even see it as sixually themed (more like pathological

), I rather felt with the guy. Until I discovered he was a major jerk. Then I laughed in his face, hard.
You can take off your clothes and stand around in your underwear. That's what it means.
while the kids are shouting "Ehh you're naked!" at you. Oh yeah, so naughty!
Also,
Spoiler Kematu of the Alik'r is under the impression that Saadia seduces a Male PC into helping her (don't know about female, but it's very possible considering the above)
It's the kinda the same for female pc's.
Spoiler He says something like "don't let a beautiful face deceive you". It's probably dumbed down for female characters, I didn't really interpret it as "don't get seduced so easily", but rather as "don't be so easily taken in by people just because they're beautiful".
And albeit very very between the lines with a lot of imagination: After defeating a dragon and running around with my weapons still drawn, I've had a guard randomly remark to me: "A guard could get nervous, a woman like you approaching with her weapons drawn".