From Sonic Retro
The Drop Dash is a technique used by Sonic in Sonic Mania and by Classic Sonic in Sonic Forces, which is best described as a "midair Spin Dash".
By pressing and holding any jump button in midair after jumping, Sonic will charge up the move, and will instantly dash off in a short burst upon landing. However, the move cannot be performed if Sonic takes damage before landing, or if an elemental Shield is active. If the move is executed by Super Sonic, a mini-earthquake is set off and the boost will be greater.
After collecting enough medallions in Sonic Mania's Bonus Stage, this move can be replaced with the Super Peel-Out or the Insta-Shield by selecting the appropriate option from the Secrets menu. These options were originally only available on a "No Save" playthrough; however, as of v1.04 they are also available for use on saved files. The player can also use all three moves at once by inputting a cheat code on the secret level select screen.
The Drop Dash was later ported to the original Sonic the Hedgehog and Sonic the Hedgehog 2 in their respective Nintendo Switch re-releases, Sega Ages Sonic the Hedgehog and Sega Ages Sonic the Hedgehog 2. It is available in all four games included in Sonic Origins, although the implementation varies slightly between releases.
The Drop Dash returns for Sonic Frontiers, making it the first time the move is used in a 3D space. Unlike the previous games though, the execution for the Drop Dash is different, requiring the player to perform a double jump before holding the button to charge the move.
According to The Taxman in an interview, the Drop Dash was designed with new players in mind.
A move similar to the Drop Dash was at one point planned for Sonic the Hedgehog 3, as evidenced by its inclusion in a prototype of the game.