Although I don't know if he exactly understands what it means, Major knows that there is a baby in Mommy's tummy. If you ask him where the baby is, he points to my tummy. And on more than on occasion I've had to remind my wild 2 year old that he has to be careful and not jump on Mommy or he'll hurt the baby. So, he knows that baby is in there.
The other night we were rocking before bed, and I told him that I loved him. And then, my super sweet kiddo, totally unprovoked, said, "I love you, Baby," and leaned down and kissed my tummy. mush...that's what I turned into. And then I smothered my #1 baby in kisses.
And then this morning we were watching 3 Men and a Baby on TV (it's been AGES since I've seen that movie), and Major was totally enthralled. He couldn't get enough of seeing the baby on TV. A little while later he turned to me, pointed at my belly, and said, "Baby, out!" Oh sweet boy. I had to tell him that baby needed to stay inside Mommy for a while longer.
I hope he's still this excited and interested when the baby does arrive this fall! =)