Hoo Hoo.

Beastie: Momma, say "hoo hoo."

Me: What?

Beastie: Say "hoo hoo."

Me: Hoo hoo?

Beastie: No, like "hoooo hoooo."

Me: Hoooo hoooo? I don't understand.

Beastie: Like "hooooo, hoo hoo, hooooo hooooo, hooo!"

Me: Ohhh. You want me to whistle.

Beastie: Yeah, whistle! Hoo hoo!