I've noticed Xanders does the same thing, i wouldnt be too bothered (he is not circumcised either) maybe 9and i know this will sounds weird) but a man penis is a lot harder (not in the "hard" sense but you KWIM? A boys penis seems to be a lot "softer" as a whole. Maybe something that changes as they get older? Honestly, i dont think its anything to be worried about, i think Xander holdshis wee in, and then needs to go, so it tries to come out in one big gush, but there's only a tiny bit for it to come through...

HTH anyways!