These are in no particular order...
Members only back room at the nightclub that's a sex / fetish play dungeon.
Job opportunity at the unmarked (sex toy) store. MC can earn extra cash giving demonstrations.
Fetish clothing (latex, leather, etc) and BDSM toys at the unmarked store or clothing store.
Threesome scenes, MC in between two men... MC and Eve double teaming someone... MC being double teamed by Beth & Jane.
Domination / betrayal from sister or best friend, MC is restrained and then "rented out" at the sex club, or trained to service the person dominating the MC.