Lesbian couple Jamie and Jill explore the underground world of S&M while their friends David and Lola compete to see who's cool enough to go through with a threesome.

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. Jamie decides to use the pseudonym Sally so she can stay anonymous but still look like she's using her real name, which apparently she thinks makes her look cool. Identifying as the butch one in a traditional butch/femme couple, "Sally" 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.