My 3 year old had began to find it extremely funny to drop his pants and shout 'Willy!' ever since he's been potty trained. We worked on this and I thought it had stopped as he doesn't do it at home anymore but now his creche has told me that he still does it there and still finds it funny and that there has been a complaint made by another parent. They said if he doesn't stop doing it he may be asked to leave. I don't know what to do, I've spoken to him about it but there's only so much he understands and since he doesn't do it at home I'm struggling to think of a way to show him this is not okay? Just feeling a bit blindsided by this all and looking for some advice.