1) (adj.) Ignorant of or unfamiliar with kink in general. (I showed my vanilla sister in-law Two Girls One Cup, and that's why I'm not invited back for Thanksgiving.)
2) (noun) Person who is ignorant of fetish. (I'm so going to nail that hot vanilla.)
2) (adj.) Sexual activities unrelated to kink or fetish. (Since I started sleeping with my sister-in-law, our bedroom activities have been mostly vanilla.)
3 Delicious ice-cream flavour. (He slowly licked the vanilla ice cream from his sister-in-law's navel. It was hot.)