Footsies, playing footsies or footsie is a practice in which two (or more) people use their feet to play with each other's feet. This generally involves slipping their shoes off under a table and rubbing their bare feet and soles against one another or up their partner's cheek. Footsies generally is used to flirt with sexual partners, though it can also be done without an erotic intent as when young children will play with each other's feet in school.
"Playing footsies" can also mean that two people favor each other over others, such as in a card game, politics or other group activity in which people are not technically paired off. Doing so tends to give an unfair advantage to the two individuals over the rest of the group.