Mark of Phlegethos( Fiendish Codex II: Tyrants of the Nine Hells, p. 85)
The disturbing infatuation of physical pleasure and pain has indelibly touched your mind, enabling to draw strength from your own suffering, as well as that of others.
Brand of the Nine Hells (FC2) , allegiance to Belial or Fierna,
You gain your master's or mistress's penchant for perverse sensuality. Whenever you take or deal damage, you gain 1 pleasure point. You can spend a single pleasure point as a swift action to gain a +4 bonus on your next attack roll, save, or ability or skill check. Accumulated pleasure points disappear at the end of the encounter.