Ass-to-mouth has crept into amateur porn too. I think they presume the viewers want to see whats popular.

I'd rather drink my own blood than do ass to mouth. The reminder of getting food poisoning a couple of times is all it takes to do me in on that idea.

I've seen viral porn on efukt.com where the guy has the other chicks shit on his cock and someone else actually gums on it. It's beyond words what people will do for money. I'd rather see a bondage flick because most of the time the people involved are getting really turned on by it.

Xtube has become chocked full of their professional porn clips, many of them ass to mouth these days.