If a campaigning politician wants to pander to a crowd of pet owners, he might deliver a speech while embracing his own pet poodle. To pander is to appease or gratify, and often in a negative, self-serving way.
The word pander began its infamous history as the name of various characters. Pandaro was a character in Boccaccio’s Filostrato. Pandarus was a character in Chaucer’s Troilus and Criseyde, as well as in Shakespeare’s Troilus and Cressida. These literary works all tell the tale of star-crossed lovers, and the namesake of pander is, essentially, a go-between whose motives don't seem entirely pure.