Bound and Sex
Realistic lesbian sex is in short supply in films. Bound, by having its sex scene choreographed by Susie Bright, can be considered to be pretty close to what "real" lesbian sex is like. The sex scene can be perceived as feminist to a certain extent. The scene is interesting as the visibly butch character is not in the dominant position; stereotypically, butch would be considered to be dominant over femme, due to concepts of heteronormativity (one partner "must" be filling a "male role" and the other a "female role"). However, this scene very obviously differs with that concept, by placing the femme character in the dominant position. If their roles had been switched, the scene could be perceived to have been simply fulfilling stereotypes and not realistic. It also would not have indicated the complicated nature of the characters' relationship.
The scene complicates the idea of femininity. In a traditional, patriarchal sense, to be feminine is to demur to men, to be seduced and not be the seducer. But in this case, the femme seduces the butch; Violet is the "aggressor", and takes the dominant position. What this suggests is that visible cues of stereotypical femininity are not necessarily indicators of actual "femininity" (in the stereotypical, inaccurate sense).