Josh broke the original story here.
DR TRIP: “If you go out and masturbate dogs – I was very good at this when I was a boy-the dog will love you to pieces because the dog has no efficient way to masturbate. He loves the orgasm as much as anybody else but he can’t self produce it. Now you just do this a time or two. The dogs do various things. You try this on all the neighborhood dogs, they all turn out to be different. Some dogs will always expect or try to talk you into doing it. They’ll come to you. Other dogs will come to any human and say, please touch me here in a certain kind of way.”
It may be an overgeneralization, but I’m going to go out on a limb and say that someone who jerks off dogs for fun can’t be trusted to present sexual matters honestly.