Everything that he owns and wanted to have are “MINE”. Right now he asserts his territory and his ownership of things by saying a loud and confident “MINE!”.
He gets in a bind at timnes when there are other kids playing with him. It is also an issue at Toy Stores and Playgrounds where he get irritated when other kids uses his favorite stuff.
I try to plead with him and ask him to share but my request are all for naught. If he wont get his way he will cry loudly or throw tantrums and it goes without saying that it is not a good sight.
Goodthing it is just a stage, in a year or sooner he will slowly learn to let go and will start to share. Sharing is one great step towards cooperation and building friendship and a trait every kid needs to understand.