Looking to place the man in a het line. Something along the lines of Spartacus or Conan the Barbarian mythos. My male slave (possibly a gladiator?) takes part in an orgy to honour the gods, to please his Domina. The participants are covered in body paint and their faces covered by masks. But his Domina has a cruel twist for him - as he is matched with his daughter or sister, and they fuck before the assembled ladies - only to have the truth revealed mid coitus.