Cian has been tt-ing for a couple of weeks now and is at the point where if he has nothing on (no undies, no nappy) we have NO accidents

- he even started doing poos on the toilet over the weekend so yay!!
But - the minute we put undies (or even shorts with no undies/no nappy - commando style) on him, he will just stand there and watch it leak out. I'm wondering if he's confused and thinks that any cloth around his bum is a nappy?
Has anyone had this or have any ideas how we can progress onto the next stage?
He's at daycare twice a week, and obviously they can't let him run around there with nothing on! So really need to move forward...
Cheers