I hate ta break it to yas-

But 'it's' ALWAYS been about sex. lol - Since the verrrry beginning.

This photo is from Pompeii, which was buried by a volcanic eruption in 79AD.



*I highly doubt this penis symbol was supposed to be a detour arrow for construction! :)

I quickly found loads of other examples but they're too naughty to post.
Having studied ancient history, man - this stuff is everywhere. On vases, in sidewalks, on walls - since the beginning of time - folks have been obsessed with sex.

On doing a search for 'ancient erotic art', I came up with this link - which is pretty interesting at quick glance. It describes how erotic art was a constant for so many ancient cultures:
http://mcs.ca/vitalspark/2010_conciousness/208ta07.html