puffed-cheeks splutter

What a parent or other older relative of an "innocent child" does when said uninhibited youngster blurts out a clever "in yer face" remark/response that said grownup and other observers find shockingly amusing.

It's always amusing when someone performs an involuntary puffed-cheeks splutter, but it is even more hilarious if the person happens to be taking a drink of water o r other liquid at the time, resulting in an enormous :"geyser" followed by a long bout of hacky coughing.