5yo pulled his pants down at preschool

My son has being showing behavioral problems with his new teacher at preschool. His old teacher, who he'd been with for a full year, recently left and has been replaced by a new lady who seems very capable but a little less 'coddling' with the kids.She's had complaints about him every day for the entire week he's been with her, which has been very concerning. Like most five year old boys, he can get rambunctious and rowdy and he tends to lose focus easily, but this is the first time a teacher has had a serious comment on his behavior. In the past we've been told he's very friendly, confident and polite. This week we've been told that he's been lazy, rude, manipulative and disruptive.Yesterday, I was horrified to learn that he pulled his pants down in the classroom, in front of his teacher and other children. He also lied and said another boy did it, when his teacher clearly saw him do it himself.I'm not sure what to think. Whatever his motivations were, it's totally unacceptable, and he's well aware that private parts need to stay private.I discussed this with him and took away the TV for the evening. I don't know what else needs to be done to prevent this kind of behaviour from happening again.My ex (my son's Dad, who shares joint custody) wants us to pull him out of there and start him in a new preschool. He has a few reasons, one being the fact that he loved our son's old teacher and doesn't see any other reason to keep him there now that she's gone.I disagree. I don't think this new problem will just end by switching preschools. And our son's been there for as long as he can remember. We would be taking away the one consistent aspect of our son's life. (he's being flip-flopped between homes every three days - and routine and consistency is not as easy to attain for us yet)I'm so worried and stressed and feeling pretty desperate. Sharing custody has been a nightmare for me, but my son has been so resciliant and adaptable to change, and has always seemed to be thriving despite all the moving pieces in our lives.Sorry for the length of this. If anyone out there has any advice, I'd really appreciate it. via /r/Parenting http://ift.tt/2nv2kAi