Play is used to describe BDSM activitities that are not necessarily sexual or sexually-motivated. It is normally used to indicate SM activities but might refer to aspects of sexual or dominance & submission roleplay.
Play can be compared to music, with each sensation like a note. Different sensations are combined in different ways to produce the total experience. Creating a pleasurable sensation experience has a lot to do with a competent top and the bottom being in the right state of mind. Trust and sexual arousal help a person prepare for the intense sensation.
How dominant or submissive a person may be in their regular life does not determine their preferred role in BDSM play.
BDSM play often includes the psychological pleasure of fetishes.