A rare skill most commonly seen on Vampires. That description is quite long, so let's use an example to break it down.
Our Vampire is fighting an enemy who's been cursed for 3 turns.
Since the Vampire is engaging the enemy, it starts with 1 ap.
DrainCurse doesn't use any ap, so we're going to attack first, because...
DrainCurse transfers the cursed status from the enemy to the Vampire.
Since it had 3 turns on it, the Vampire restores 6 to both health and mana.
The Vampire also gets 1 ap, but now we're cursed we're going to seduce the enemy instead of attacking, since...
DrainCurse raised the enemy's lust by 15, so we're going to top that off.