i've made ds 1 clean it up before. he's 6, but has never 'pointed percy' in his life. his idea of peeing is to stand with his hands behind his back having a good look round. i blame his father. thank goodness the other two are girls.
DS1 started doing this recently on and off, not for the same reason but I suspect its a phase some of them go through. He gets told off in a stern voice (nothing more then thats naughty we all wee on the toilet) so he knows its not acceptable and then loads of praise and gold stickers on his jumper for weeing on the toilet. Seems to have worked.