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."