Lecherous (3.5e Flaw)
From D&D Wiki
Summary: You have an irresistible urge to boink.
Effect: Whenever a character sees an attractive member of a preferred gender (with a Charisma of at least 14 or higher), the character must succeed on a Will Save (DC of 15 + creature's Charisma Modifier) to avoid immediately approaching them and trying to seduce them. Being the lecherous filth they are, they usually, though not always (a Sense Motive check is made by the victim to determine), come off as a pervert to their prey and in which cases a -2 modifier is applied on all rolls while interacting and trying to seduce their new acquaintances. If the acquaintance is an enemy then a -5 on attack rolls if attacking.
Benefit: Bonus Feat