Why during sex we are pushed towards licking the ASSHOLE, from where SHIT comes out.
Why it looks so cute and tight, all smashed and pulled in, all wrinkly and dimply and forces us to go down on it?
TC actually had a post a while back that makes sense of this. I don't remember the exact details, but I think it was found that the "disgust circuitry" shuts off during sex. Maybe even flips, considering people like being pissed and shit on. But there is some correlation between "nastiness" and sexual pleasure.