How to make a green triangle in 4A or Offstring yo-yoing like these
From 0:58-1:03
He throws the end of the string around the middle and holds onto the end of the string and the top right corner of the GT.
I’ll make a tutorial.
He whips the string around, and the loop goes under the Yo-Yo, and goes up to catch on into a GT.
Here I made it:
Don’t you do Offstring while the Yo-Yo is spinning? 
Yes but I am not allowed to do offstring in my house. I am only allowed to do offstring outside and the my camera is on my computer.