How about a fantasy of being buried from the neck down, naked, in an ant hill? Does that count? Or for that matter being staked out spread-eagled over one.
I also remember some very early torture fantasies of being locked inside a narrow coffin-like metal box set horizontally in the ground, but with the top exposed to the heat of the sun. Poe's "The Premature Burial" story (and movie) bothered me a great deal--nightmares and such--as an adolescent, 11 or 12.