possible hyperventilation (Mom, not baby)

Elliot has a new trick full of fast breathing, a scrunched up nose, and some snorts. He now does it all day long. It is usually intermixed with some high pitched squeals, and some "ba ba ma ma."
We've decided not to encourage it anymore for fear he's going to get really light headed. He can go on some long stints of it without a real breath. He thinks it's the best thing since pureed pears.