Hi E.!
It sounds like he might be "copying" something. Uh-oh! He may not be around the most appropriate behaviors at Daycare.
If I were you, I would make a few surprise visits during the next few days to "reassure" yourself that all is ok at the Daycare.....or not.
It has been my experience, that when boys are FINALLY potty trained, especially with the pee-ing part of training, then the only other thing to work on is "listening" to their body to avoid accidents, and any night-time wetting. But, out of the blue, intentional pee-ing on oneself, sounds more of an "emotional" issue, than a potty training issue.
I know that during the summer, Daycare's usually have more children~ and alot of times, their own children are helping out the Daycare provider.
I don't want to say any of the "other" things running through my head, I just think it's a good idea to make a seriouis effort to go to the Daycare OFTEN to make sure your son is ok...
Good Luck, E...
:o) N.