The loyalty test

I just came with a mate to make a pair of arrangements. We get onto the subject of sex pretty quickly. It's quite amusing to hear the other side, as his girlfriend is one of my best friends. He's convinced that he would never cheat. But then I go all out. It doesn't take long and I've got him to the point where he would even meet up with me. I admit that his cock makes me pretty horny too. But when he really gives up control, I have another ass up my sleeve, which unfortunately costs him dearly...