It can be performed with Mario in the front and Luigi in the back. Luigi will jump on Mario's head and start bouncing. If the Button is pressed, Mario will hold onto Luigi and jump high. If the button is pressed, Luigi will jump back behind Mario, cancelling the move.
If the Mini Mario ability is used, then Luigi attempts to use the High Jump, he will act as though the A button was pressed normally. However, if Mini Mario jumps while Luigi is above, he will hit Luigi like a Coin Block. This will create one coin per hit, but at the cost of a single drop of Health Points of Luigi's health per hit. If Luigi is at a single Health Point, there will be no effect, and Luigi will yell in pain.