I hadn't heard that, but I will look into it, thanks for the tip.
And to be perfectly honest, I am only guessing that there is a testicle left that hasn't descended and wasn't removed. It's because when he got to be two or three years old (I can't really remember - he was neutered at 5 months, though), he started doing this weird thing where his male organ gets hard and turns purple and he starts to hump the air and he can't stop. He doesn't try to hump our female dog or anything else... he just tries to walk around and his body seems to be doing this humping motion involuntarily while he is walking. It's kinda funny and sad at the same time. He looks so uncomfortable and he bites at his swollen organ and wants to stop humping and can't. And, except when that happens, he's never humped anything or acted overtly "male." Anyway... I have researched it a bunch on the internet and all the people say the same thing - undescended testical that was missed during neutering. But, I guess it could be something else.
As for the cat... I have known cats that continued to spray their whole lives after being neutered if they had already started before the surgery. Like other people have said, though... it'll probably go away with time.
