Mothers with 2 under 2?

My boys are 20 months apart. While I was pregnant, my oldest would lift my shirt and kiss my belly and say 'baby'. Even after the baby arrived, he would still lift my shirt and say 'baby' but he would also go over to the baby and say 'baby'. So I guess he figured we got a baby but there was still one in my belly. When the baby naps and starts stirring, I pat his bottom and say 'shh' to see if he'll go back to sleep before I pick him up. My son does that for me if he gets to the baby before I do. And he'll even try when the baby is still asleep. He lays on a blanket and reaches back to pat his bottom the way I pat the baby. And he climbs on my lap, puts his head on my shoulder, and reaches back to pat his back as if I'm burping him when he sees me burping the baby. He also pretends his teddy bear is a baby. He'll wrap it in a blanket and carry it around. He'll put it over his shoulder and burp it. He'll pat it's bottom and say 'shh'. And he'll put his bear to my for me to feed it (he just did that one a minute ago).