A play in which declarer uses trumps in both hands to ruff losers rather than drawing trumps. It is usually correct to play off side suit winners before starting to crossruff to stop opponents from discarding those suits and later being in a position to ruff declarer’s winners. A crossruff works best when most of your trumps are high trumps.
As South, you play in 7♥. West leads a trump. You should win in hand (you do not want to use dummy’s lowly ♥3 for ruffing) and cash the red ace- kings as well as the ♣A. You will then ruff clubs in hand and cards from the pointed suits in dummy and make the rest of the tricks.