I'm in the same boat you are!!! My son first did this for a sitter I had in my home about 5 mths ago. I thought it was a 1 time ordeal! About a mth ago, he did it again and has done it 5 times since!!! It's SUCH a nightmare! I feel your pain! It's so frustrating. I don't know the solution either. If anyone gives you any good advise, I'd love to have it!! (____@____.com)
I have asked other mothers and have found that a lot of children do it. (not all) I guess it's just a phase some of them choose to go thru, for whatever reason?
Good luck and please pass on any good advise you receive!
J.