From Halopedia, the Halo wiki
The trick can be performed with a Radar Jammer, a Flare, a Deployable Cover, a Trip Mine, an Auto-Turret, or a Power Drain. To perform it, a player would first look down, and then jump. At the peak of their jump, they would deploy the equipment item (by pressing X), and then quickly press A again. The button presses cause a player to jump off of the equipment as they deploy it. Skilled players can reach farther distances by running forward while performing the glitch.
Players using a Spartan player model cannot reliably perform the trick with a Power Drain, as Spartans throw Power Drains farther than they do other equipment. Only Elites can use Power Drains for equipment jumping. There is also an element of risk associated with the use of a Power Drain, as even in the event of a successful jump, the jumper would still be left unshielded and vulnerable.