anal
Play that includes the dominant inserting objects or body parts into the anus of the submissive. Often the dominant will use anal play to train the submissive to take strap-on in the anus, generally starting with small butt plugs and working towards larger objects. This can be a part of sissy or slut training, and can also be used to humiliate the submissive.
In my personal interactions, when the energy is right, I enjoy using anal play as a tool for training and humiliation. Nothing feels quite as powerful as thrusting into a submissive. I love how vulnerable and open my sub has to be for anal play. I do not offer sexual services in pro-sessions.