Loser on loser : discarding rather than ruffing
A technique the declarer can use in a trump contract.When you fear an overruff, discard a loser and let your opponents make the trick.When ruffing high may promote one of your opponents' trump cards... use this technique.
Example
You are S, playing 5♦. West leads J ♣, East covers the J with his Q and replays Ace ♣. Which card to play ?