Grudge Finger

The act of cheating on your spouse by having sexual intercourse "Doggy-Style" while simultaneously finger banging your new partner's butthole with the Ring Finger. This act is followed by a conscious effort to not wash the relevant finger.

Bryce: So how are things going with Mandy? Made up yet?

Nate: We're doing a lot better. I got sick of sleeping on the couch so last week I went out to McGarvey's, picked up a skank, and gave her the 'ol Grudge Finger. On Tuesday I gave Mandy a neck massage and she said I needed a manicure.