Git good, son

If the follow up to you saying you're done is them demanding to keep going, that is coercive and fucked up. I wouldn't suggest lying in response unless you never plan to see them again, though, or if you feel safe and plan to address it later. It's just as fucked up to keep up with the lie afterwards as it is to be coercive, imo. Both play coercive, indirect ways of refusing respect, and the tit-for-tat dynamic risks setting up a breeding grounds of resentment for at least the person maintaining a lie. It also denies the coercive person the opportunity for growth.

Okay but if that's his response then put your foot down and tell him in no uncertain terms that you are finished

The balls often get neglected. Give them a little gentle attention too. Basically, do the kind of things that would feel good if done to your breasts (cupping them, light scratches and tickles, a gentile squeeze, a medium tug, ect.). Combined with a halfway decent stroking or sucking, it'll take care of most guys in pretty short order. Any other questions you don't want to ask someone who you'll have to see again? Happy to educate. I'm a male nurse if that somehow makes it less weird.