Jake, Do You Want To Play Train?

Ben and Matt include Jake for the first time in what they are playing. It went something like this:

Ben: "Jake, do you want to play train?"
Jake: "Blrghafff"
Ben: "You sit here and be the little red caboose"
Matt: "Jake! You're on our train!"
Jake: "Da, da, da"
Matt: "Choo, choo!"