Marking His Territory

Kross has started getting very mad if I try to dry him and put his diaper and clothes on after his bath, so I let him crawl around naked for a few minutes. Well, he's started peeing on stuff. I figure since he just peed in the bathtub, he won't need to go again, but I'm wrong every time...in fact, he makes himself go again because I hear him grunting to push it out. And he likes to stand up to do it.