It was just a smart-mouthed slip of the tongue that brought Brianna and Amy together. Call someone mistress just once and she seems to think she's permanently in charge. Not that Amy was complaining. Not one little bit.
When Brianna starts complaining about Michael and his inappropriate advances, Amy quickly realizes that the sergeant doth protest too much -- especially when those complaints are accompanied by soft sighs of frustration.
Ever ready to please her mistress, even when Brianna hasn't quite figured out what she wants, Amy takes control, proving that even the most submissive girlfriend knows how to get her way.