More sincerity.

No need to copy the sighs of pornstars, just allow yourself to express pleasure out loud. It doesn't mean you have to say dirty things. You can say what you like, but not in the form of a command “Stronger!”, But, for example: “I love it when you move harder.” Yes, and he will like simple ahi-sighs if they are sincere. You will be surprised how much they can inspire him to exploits.