My Son is Now a Man

Well if not a man then definitely a big boy. The other day I was getting him ready for a bath, I stripped him down and turned to undress his sister. In retrospect this is where I went wrong. I finished undressing A just in time to see S lean over, brace himself on the wall, let go a giant stream of urine and laugh hysterically. Only a boy would think peeing all over the bathroom scale was hilarious. Do you think it's time for potty training?