Poison Kiss (3.5e Feat)
From D&D Wiki
 Poison Kiss [Abyssal Heritor]
The Succubus heritage in your blood turns your kiss into a life-sucking weapon.
Prerequisite: , Succubus Heritor
Benefit: If you kiss someone, that person must succeed at a fortitude save against poison with a DC of 10 + half your character level + Cha bonus or take 1d4 points of Strength damage, and make the same save one minute later or take 1d4 damage again. This ability is usable once per round. The target of the kiss must be willing, or the user must succeed at a touch attack during a grapple. This is a supernatural ability.
Special: This ability is hard to control, and you run into the danger of poisoning everyone you kiss. You must succeed at a Will save DC 25 to suppress this ability. You gain some control as you become stronger, and the DC is lowered by one for each Abyssal Heritor feat that you have.