People who act good but deep down are bad .
Someone who will help you so they can fuck you over.
That handy man I hired seemed so nice but in reality he was a dark side lurker who stole everything.
More adventurous types of sex, while staying in the realms of mainstream - e.g. Toys, risqué locations, butt stuff and the like.
I'm not kinky but am on the dark side of vanilla...