From pygo- + -phile.
pygophile (plural pygophiles)
- A person with an intense aesthetic and/or sexual preference for the human buttocks.
1985, Barry Balwdin, Studies on Greek and Roman History and Literature, J.C. Gieben, →ISBN, page 357:[…] Pompeian wall-painting and a terracotta from Hadra display the heroine half-naked, as does a mosaic from Praeneste, whose back view is a pygophile's delight; […]
2008, Dick Wimmer, The Wildly Irish Sextet, Soft Skull Press, →ISBN, page 129:"And so is this," nuzzling down her buxom body and lustily gnawing these sleek, melonous swells.
"Such a pygophile y'are."
2013, Jesse Bering, Perv: The Sexual Deviant in All of Us[1], Farrar, Straus and Giroux, →ISBN:For example, my first exposure to an erotic outlier was with a hebephilic pygophile who also had a touch of frotteurism.