When Jamie finds out her girlfriend Jill has spent time exploring BDSM, her insecurities about falling behind in the bedroom push her to propose that they start going to underground clubs. Identifying as the butch one in a traditional butch/femme couple, Jamie assumes she will take the dominant role in their escapades, with Jill as her submissive, but Jill has ideas of her own.

Meanwhile, their friends Lola and David start dating the polyamorous bisexual Sebastian, who proposes to have a threesome. They quickly agree without planning to follow through, expecting the other one to back out first. A provocative and hilarious ride, S&M Sally details the unexpected journey that happens when your insecurities push you outside of your comfort zone, leading you down a path for which there is no going back.