1) After sex, it is the waiting time(medically known as the refractory period) until the guy is ready to "practice his craft all over again." In most cases both parties are still slippery and sticky from the first time, so he just slides it in and repeats the process. Best outcome is that the dude knows what he's doing and the woman doesn't get to annoyed.
2) Doing something again even though the first time was a complete and total failure. Unfortunately this time, it is even worse.
1) Girl: What are you doing back there?
Dude: Ya up for a slippery repeat? I know I am!"
2) Dude #1 "What the hell is he doing here? Didn't he smash into some cars and fuck them all up?"
Dude #2 "He sure as fuck did. Guess he's a slippery repeater and must learn the hard way."
Dude #1 "A slippery repeater and an asshole? Great combo!"