The point is to not have any nibblers because the item is worth say $100.
You bid $100, your buddy bids $101. And the next highest bidder is say $15 because the two of you bumped it higher or as high as the item was worth.
When your buddy retracts his bid you become the winning bidder for $15.50.
No nibblers because the price was so high and you win it for $15.50.
This is of course against the rules.