If I was your Girlfriend, by Prince off of Sign o’ the Times. He is definitely helping his girlfriend get past sleepovers and pillow fights and gossiping together…
Couldn’t find an example of the original on youtube - I think he has his songs off of their for the most part…
Sex by Berlin
Grace Slick sounds rather breathless through much of Miracles. I think it’s her finest vocal performance.
The Doors: The End.
The end of “hungry like the wolf” by Duran Duran
“We’re so hot, we’ll melt your popsicle . . .”
“Feelin’ Love” by Paula Cole
can’t remember exactly, but I think there is sex in the background of Meat Loaf’s* Paradise By The Dashboard Light*
Raze - Break For Love near the end
Boyz II Men - Uhh Ahh
Peter Gabriel’s Blood of Eden
What do I win?
Stop right there!
Close, but no cigar. 
Prince has songs about sex? Color me surprised. And purple.
Although I don’t think the goal is titillation. I knew one guy who thought that that song was hot, but we didn’t talk much as he was a bit of a motherfucker.
I’m fond of Sweetest Goodbye by Maroon 5.
Liebestod from Tristan und Isolde by Richard Wagner.
You can’t tell me that’s not an orgasm.
“60 Minute Man” includes “15 minutes of blowin’ my top,” which is . . . impressive.
Gene Vincent - Woman Love has some suggestive moaning in it.
Bonnie Raitt’s cover of a Chris Smithers number would qualify. Not only does she have the oohs and aahhs, but the guitar accompaniment is a good simulation of bumping uglies.
“More Human than Human” by White Zombie (the intro.) The extended version, anyway.
“Foxy Lady” by Jimi Hendrix.