(Ronan was singing, "diapers are not forever....diapers are not forever...diapers are not forever...")
Since he is now potty-trained and has been for a few months, I thought it was funny -- but I think it has to do with the potty-training they might be working on in school with the other kids.
Ronan: Momma, 'member when I was a baby Wonan (Ronan) and I used to poop in my diaper?
Me: Yeah....
Ronan: Dat (That) was fun!
Me: Hahaha, no. It wasn't fun.