Auto-erotic stimulation of the
anus with one or more fingers while driving a pickup
truck. For a traditional, or "urSilfen," the same fingers should then be used to pick crusty boogers out of an extremely hairy
nose and the fingernail(s) should be cleaned using an incisor tooth. Extra points for simultaneous perfomance with spouse.
"Don't look, honey, but I'll be
gosh-darned if the
odd looking fellow behind
us in the Chevy isn't Silfening himself."