xkcd

LPT: find a plausible excuse to leave gatherings in a way that seems outside your control. This gives you an exit without seeming impolite. Between my parents, if one starts asking about the dogs, that's their cue to start leaving. If they leave because "they need to take care of the dogs," the hosts won't have to know whether that means "we'd have loved to stay here but unfortunately, duty calls" or "we'd rather be spending time with our dogs than you guys."

Totally forgot "Silently getting up from the table as though you'll be right back, going around the corner, leaving the premises through whatever wall opening is available to you."