Separate heading from curvature
Heading describes the direction the companion is traveling right now. Curvature describes how that direction is changing. Imagine tracing an arc with a pencil: switching the bend does not require jumping to a new point or making a sharp corner at the switch.
That is why tapping lower on the screen does not send the companion downward. The game uses the input as a reversal, not a destination. The same action has different visible consequences depending on the heading at the moment you use it.
Use the trail as evidence
Look at the short section of trail immediately behind the body. It shows where the companion has just traveled and helps distinguish rising, falling and mostly horizontal movement. The decorative tilt of the creature is a less direct guide than its actual path.
After a flip, observe how the new section changes. If the path is still rising but becoming less steep, the reversal may already be working. Another immediate tap would switch the curvature back before the first correction has fully developed.
Include the companion’s movement style
Companions differ in pace, turning radius and vertical drift. Pip has no additional vertical pull; Moss sinks and Ember floats. The same-looking heading can therefore produce a different vertical route when you change companions.
Start by learning the relationship with one companion. You do not need to calculate circles while playing. The practical question is whether the current path, continued for a short distance, leaves enough room around the next branches. Make a reversal to change that future path, then judge what actually happens before issuing another.