This allows mid-air morphing in a 3-tile-high space in air physics, or a 2-tile-high space in water physics.
"R" refers to holding an angle button while jumping from a crouch,
to negate the vertical boost that a crouch jump would otherwise give:
1) Hold down to crouch, and continue to hold down.
2) Additionally hold an angle button, either angle up or angle down.
3) While crouched and holding both down and angle, pause and jump just before the pause hits (similar to a gravity jump).
4) Release all inputs during the pause screen.
5) During the unpause black screen, press and hold jump and diagonal down-forward.
See also: Tech Page