verb: to have sex with someone you were previously dating or hooking up with. Specifically after a falling out or bad breakup and tends to make things more complicated.

The horrible moment when you realise that you have accidentally done something very slightly wrong which has very bad (usually embarassing) implications for you. This is typically the moment of realisation that you just sent a dirty text message to a close member of family, typically your mother, rather than the intended recipient.

verb: To revert to sin or wrongdoing, especially in religious practice.

To continously return to a prior state. Can be used to define a addiction or a relationship

When one goes back to their Exs.

verb: to re-adopt sinful ways after having spent some time as a pious religious person.

What the Moonwalk used to be called, the backslide has its' roots in mime.