Easy solution: grab the phone & shove it up her twat. With that hole being occupied, you'll have no choice but to relocate your penis to the nearest available orifice - her anus. I call this "How To Get Anal From A Prostitute Without Paying Extra, by eFukt.com".
This is from the 1976 classic Water Power. It's a lot like Taxi Driver, except this Travis Bickle has a little fetish for forcing woman into doing enemas at gun point. The film is actually based on real crimes committed by an Illinois man dubbed the "Enema Bandit". Anyway he's dead now, so R.I.P you scat-loving motherfucker.