I have to say, the only thing weirder than Rex playing with toys in the bathtub like a five-year-old was how Six just stands there in the same room where he's bathing and Rex doesn't totally freak out on him. And yet he spazzes when Holiday, the one he hits on, sees him without his clothes on. That's what I don't get.
I guess because Six is a man, and people of the same gender are supposed to not be freaked out by each other's nudity, which I find odd. But who knows, maybe Six has seen him naked before and he's gotten used to it (this isn't meant to be taken pervertedly BTW).
I've also heard that even if someone you know has see you nude before and you're comfortable with it, when they become your lover or someone you crush on you're no longer comfortable with it and you have to build up from scratch