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.