Me: How do cowboys say hello?
Friend: Howdy.
Me: How do deez nuts fit in your mouth?
Alright listen up, lil' buddy. The joke is a setup for a "Deez Nuts" gag. Someone asks a question that sounds innocent, then BAM! They hit you with the ol' "Deez Nuts" punchline, which is usually a question about fitting something in your mouth, see? You probably think mayonnaise is spicy, don't you?