The taboos are there, though, so in a way pee is a cheap thrill: it feels really dirty without being any dirtier, really, than a glass of drinking water, and in many cases it's cleaner. The big thrill/low actual disgustingness quotient explains its relative popularity among "weird sex" types. It's weird but not that weird.
None of this means, of course, that you have to let him pee on you. I'm not at all comfortable with a system where if Andrea says it's not going to hurt you, you have to do it! You're going to want to ask exactly what he and the ex were up to, what he got out of it, and, if possible, what she got out of it. As long as he's willing to drop it if you're not into it, though, what the heck? Maybe you'll yike it, maybe you won't.
Got a salacious subject you want Andrea to discuss? Ask her a question!
Also, Andrea is teaching! Contact her if you're interested in (sex)life after baby classes. Her new blog is at www.gogetyourjacket.com, but don't look there for the butt sex. There isn't any.