The flip control in APM Roblox appears to be the Emote button/key, based on recent player guides and control mentions for APM/related Roblox gameplay.

What to try

  • PC: press the default Emote key/button.
  • Mobile: tap the emote icon on the screen.
  • If it does not work, check the game’s controls menu, since some APM setups or updates can remap actions.

Quick note

Some search results are about Roblox Studio flipping objects or unrelated Roblox flipping mechanics, so they are less likely to apply to APM itself.

TL;DR

For APM Roblox, the most likely answer is Emote.