The rerub of a song is a less radical reworking of the original than a remix. A rerub adds new drums, new snare, new percussion, possibly effects. Rerubs are also often shorter than the original song.
David Guetta thought he remixed Cassius's song "Toop Toop" but it's just a freakin rerub. All he did was add some bass.
Masturbating at least twice successfully in short succession
Person 1: Hey, why were you late?
Person 2: I just did a rerub, best feeling ever...!