This just involves continually saying “no” in the politest possible way. You just say it over and over again and never change your tune. An example is provided below:
Sam: Come with me tonight.
Jess: No thanks, I don’t really want to go to a club.
Sam: Just this once.
Jess: No thanks, not even this once.
Sam: But you’re normally such fun.
Jess: Not tonight. No thanks.
Sam: Go on, you’re my best friend.
Jess: Yeah, but no thanks, I don’t feel like going tonight.