An inquiry to my son revealed that the plunger belongs to a Lego porta potty he owns, as part of a Lego construction site kit. He agreed to let me use the plunger, the suction cup of which, incidentally, actually works.
As I placed the tiny plunger in one of my magic development desk drawers, I noticed some old tricky coins among the small magic detritus. One of them was the old joke squirting nickel.. Aha! Wouldn't it be fun to use the plunger with the squirting nickel! Not for the stage, of course, but for informal occasions when an impromptu gag would be appreciated.
Normally, the squirting nickel is brought out alone and a spectator is asked to peer closely at it, in order to see Jefferson's lawn - then, blast! You say, "I guess he left the sprinklers on!"
For this arrangement I might begin by first showing the tiny plunger in my hand. Then I would try plunging various things - a person's watch, their lapel, my elbow. Finally, I would retrieve some loose change from my pocket, and choose the nickel. I would ask the spectator to try the plunger on the nickel, which I hold in my hand, then, blast!
The question of patter remains for this little routine: Why do I have the tiny plunger in the first place? And why does it only work on this nickel? Or is any explanation really needed at all? All things to consider as I try out this amusing diversion on some unsuspecting acquaintances.