The inverted flam tap puts the tap after the flam in the opposite hand: lR L, rL R. The grace note and the tap before it come from the same hand, which takes coordination.
Sticking
lR L rL R
Capital letters are main notes. Small letters are grace notes played just before the main note.
How to practice it
Play the main notes alone first, without grace notes.
Add the grace notes, keeping them low and quiet, about an inch off the head.
Speed up only when every flam sounds like one thick note, not two.
The hand that plays the tap immediately plays the next grace note. Keep that hand low and relaxed.
Where you will use it
Moved to the hi-hat and snare, it becomes a popular funk groove.