We are dealing with this a lot in our house, mostly from Ethan. Ethan likes to snuggle and cuddle with me and Lucas likes to play independently. When Lucas decides he wants some one on one attention from Mommy, though, Ethan doesn't like it one bit. He'll come and push his way between us. He will pull on Lucas to move him away from me. He will push him out of his way so that Ethan can be on my lap instead. It has been for a long time that if Ethan wants a toy that Lucas has he will take it away from him, which still continues. But now he's pushing and pulling Lucas which is far worse than just taking his toy away.
Jeannie @ Living Loving Crafting