I remember when it was just this little guy. He used to play by himself a lot except for when he would stand, hanging on to my legs, crying up into my face. That's the way it often goes with a firstborn.
I cringe when I remember how often I would call, "Leave her alone! What are you doing to her? Why is she crying?"
That is, I used to say that until one day, I watched. On my honour, that dear old boy wasn't doing anything to her. If anything, she was only responding to an invasion of her personal space by a big brother coming in to give her a little kiss, or something.