Flex the finer points of your character's personality; things that show nuance. The fact that your character is doing nothing but groaning and moaning is in itself a problem. How do they feel about the character that's subservient to them? Are you a regular couple into light kinky play? Offer gentle strokes of affection as according to the relationship. Are they your nonperson property? Deny them social attentions like eye contact and be as rough with them as is required to enjoy the act to its fullest. Are you specifically trying to subjugate them through fear? Seize them by the chin or neck and don't permit them to break eye contact for the entire act. Have you no time for their pitiful offering as you attend to things you care more about, like business or a hobby? Keep doing whatever it is that's more important than them, even if you have to put a client on hold for a few seconds so you can cum without letting them realize what you're doing. Is your goal to humiliate them? Make sure they know they've got a camera on them; force them to do things for whatever audience is or will see the recording, even if they don't exist. They don't know that. Draw attention to their flaws; make comments implying that they owe you for allowing them to service you, not the other way around.
Any of these actions can be expanded upon or delved into for more detail. Hell, you could combine any of them.