This might sound really silly, but i have never seen it before and i'm not sure if it's just another development he's trying to go through. My son is 7 months old, he isn't crawling yet but he can sit up on his own and rolls all over the floor. However, when he's laying down, for the last 2-3 weeks (maybe a little longer) he reaches his arms up to the sky and puts his legs up in the air bent, sticks out his tongue and kind of blows bubbles. i'm not sure if he's doing this because he's trying to learn how to sit up on his own or what? Has anyone else ever seen this? Do you think i should be concerned?