Bit of a weird one with my 3 year old

[dwr]

My 3 (nearly 4 year old) has been out of nappies and reliably toilet trained for a year. In the last few weeks he's started weeing in things. He first did it when I left a mop bucket in the lounge, I asked why he did that and said we wee in toilets. I then caught him doing it into an empty drinks glass. He was then caught yesterday weeing into his bowl after finishing his cereal and this morning into an empty Doritos packet! I really don't know what to do? I don't want to cause a big reaction so I'm just silently removing and cleaning up with just a "we wee in toilets". I promise I'm not a piss troll before someone throws that at me, and I'm not fishing for stories of peoples kids pissing in or on things, just if someone has had this how did you get the behaviour to stop? It's really throwing me to be honest I don't know why he's doing it

I'm a teacher and it happens occasionally at school (weeing in a bush) but ALWAYS after someone has shown the kid weeing somewhere not in the toilet. I'd just ask him in a nonchalant way if he knows anyone who doesn't use the toilet. He will have picked it up from somewhere!

I wouldn’t silently put up with it, I would make it very clear that it’s dirty and unacceptable. He’s old enough to understand that.

But like anything, it’s just a phase and he’s doing it because he has male plumbing and he can!

Does he do stand up wees?
Mayb he sees it as no different if he does, or mayb he has seen people doing stand up wees.

I think boys might go through a stage of being excited that they can literally go anywhere they please. My son did this. Once. Actually he weed in a pint glass then offered me lemonade. I hit the roof and he never did it again.

my other son had an obsession with wanting to poo in the garden like the dog. We let him. But to be fair he’s autistic and just had such an obsession that we knew as a one off it would be ok. He was disgusted at himself after. We buried it and never spoke of it again. 😂