The slang term used to describe when someone has sex with their ex, meaning former boyfriend or girlfriend.

This is often done while the individual is on the rebound and does not desire to take the time to seduce a new lover, but rather wants cheap, easy sex. This can be an inviting prospect, as the genitals don't have a concience but they definately have a memory. Though experience and socialization generally leads people away from Ex Sex, as it is looked down upon and often leads to drama.

Often the motto of someone who habitually has Ex Sex is Recycle, Reuse, and Abuse.