A "rescue call" is set up in advance of a family gathering that you don't want to attend. This arrangement involves appointing a friend to call you at a pre-determined time, providing you with an excuse to leave early. A well timed rescue call occurs immediately after you have eaten.
Rescuee: Thanks for supper - the meat was good eh? Woosh!
Rescuer: Hey man, here's your 6:30 rescue call.
Rescuee: Oh hey. How are you?
Rescuer: I'll see you in a bit. Don't forget to pick up some rolling papers on the way over.
Rescuee: Oh, yeah...don't worry, I'll be right there.
Rescuee: Fff, I gotta go and help someone with some school stuff. I guess I'll see you later eh?