Much like a molecule, which by definition is the smallest fundamental unit of a chemical compound, a testicule is a small male testicule. They cannot be seen with a microscope, similar to that of a molecule.
Brody: I was giving my testicules a massage last night. Too bad they are smaller than the wavelength of visible light!
Kevin: I bet you could piss it out like a kidney stone.
Him: *For the third time in 3 minutes* “Fuck babe, you look good as helllll.”
Her: “Are you testiculating?”
Him: “Yes. Come help me do something about it?”