It is possible to perform a second jump mid-air by letting your shield get hit by a Remote Bomb explosion. To do this, first place either Remote Bomb on the ground. With your shield equipped, detonate the bomb with L and at the same time perform a backflip/sidehop/fronthop with ZL + X + a direction. If timed correctly, you should be able to get the second jump, from which you can then Shield Jump to gain even more height. The most optimal combination for height is first a backflip and then a fronthop - but two fronthops may be more beneficial in some scenarios to gain slight distance. It is important to note that this trick may not be performed liberally, as it requires a very powerful shield. The overwhelming majority of shields available cannot withstand even a single attempt before breaking, the Hylian Shield being the only exception.