How do you know a 4 year old lives in your house?  The word “butt” becomes the funniest word in the world.  Anything with “butt” affixed to it is instant comedy gold.

Pickle + Butt = PickleButt

Donut + Butt = DonutButt

Bunny + Butt = BunnyButt

Say loudly and fall over in a pile of giggles.  Continue ad infinitum.