When performing Hop Jump, Sonic corrects his own body while he moves upward in midair so that it becomes more aerodynamic. Doing so makes it easier for Sonic to move through the air, allowing him to launch himself higher into the air regardless of momentum.
In order to execute Hop Jump in gameplay, the player must first have Sonic launched into the air through gimmicks such as through Springs, Ramps, trampolines etc. In all of the games it has appeared in, the player then has to press while holding up on to execute the Hop Jump. While using Hop Jump, however, Sonic cannot attack enemies.
Sonic Advance 2
The Hop Jump made its debut in Sonic Advance 2 as Sonic's upward Mid-Air Trick Action. When performing the Hop Jump in this game, Sonic looks upward, bends his legs slightly backward and raises one of his palms as high as he can above his head.
Sonic Advance 3
The Hop Jump reappeared in Sonic Advance 3 as one of Sonic's Special Actions. In order to allow Sonic to perform the Hop Jump in gameplay, Sonic must have Tails as his partner. In this game, Sonic's performance of the Hop Jump is the same as it was in Sonic Advance 2.
The Hop Jump returned in Sonic Rush as one of Sonic's standard moves. In this game, Sonic cannot take damage from touching enemies while he is performing the Hop Jump should he enter the space occupied by enemies, though he is still susceptible to direct attacks from enemies. In this game, Sonic's performance of the Hop Jump has been slightly altered; when using the Humming Top in this game, Sonic does not raise his hand and he instead twirls around himself.
Sonic Rush Adventure
The Hop Jump made another reappearance in Sonic Rush Adventure. Here, the Hop Jump's mechanics are the same as they were in Sonic Rush. In this game, Sonic's performance of the Hop Jump are the same as it were in Sonic Advance 2 and Sonic Advance 3.