Next step of outterfly moves.
When you do butterfly, there 2 positions. Right poi top, or Left poi top. Thread the needle (TTN) is the move that you alternate these 2 positions

Begin with Inward, Right poi top

1. When your poi cross at the top, your right hand goes forward.
2. Until poi goes around a circle, right hand is on front, left hand is on behind.
3. When your poi cross again, now your left hand goes front, right hand comes behind, change the position before poi goes bottom.
4. When poi comes top,you change position again.
5. Repeat.

Poichi exercise butterfly is exactly the same move without poi. so if you have any problem, go and practice poichi exercise.
For outward TTN, practice upside down from inward.