When a girl just sucks you off and goes her way without giving even a number or any info,leaving u with messed up emotions.More often than not it would be a swallow and run but that does not rhyme with hit and run and girls dont always swallow hence spit and run.

Literally everyone, ever. Including the writer of this definition.

Applying one's own saliva to the penis to facilitate sexual relations with an unknowing and traditionally unconscious sexual partner.