After receiving a blow job from a girl on the top bunk of bunk beds, the act of jumping down to the ground in such a way that your slobbery, erect penis slaps the person occupying the bottom bunk in the face.
Now you are really gonna get it... I was only going to shroom slap you, but now I'm going to give you a slobbery long john!
An unreasonable request added to a task by someone who wishes you to fail. From the Monty Python "Knights who say Ni" sketch.
Bob: "In order to convince me that global warming is real, you will have to show that all temperatures everywhere on the globe are setting records at all times."
Bill: "Uh huh. Would you like a Shrubbery as well?"