The delicate act of separating the
jaw from a decapitated
head (taking care to keep the tongue in tact) and then proceeding to "fuck" the esophagus; therefore
fucking just the skull.
"I went to the cemetery last week and found an excellent skullfuck!"
"The best
time for a proper skullfuck is when the
hole has been aged for about
15-25 years of age."
"She looks like premium skullfuck material."