ikn what a thumb grind is but what the grind where the yoyo is like the other way around, like the yoyo is up and down. sorry if this sounds dumb i just dont know what its called.
what do u mean it is balanced on your thumb or wat do u mean
Like the one Andre does in operation DM? Its a normal TG just down parrallel to the ground. Throw a UFO and stick your thumb in.
yes thast exactly what i was talking about. its hard to keep the yoyo stable though i guess ill just practice
or u could just throw a breakaway but throw it very crooked so its leaning back and stick your thumb in there
It is still a thumb grind 
But at least I have heard many people call it an Inner Ring Grind because you use the inner rings on the yoyo to do it. I’m not sure but I doubt you could do it with the regular or outside rims because they would be too far away from the center of gravity, but I could be wrong.
If it goes around your thumb in a circle then pull back a little with your throwhand so your pulling the yoyo back on the thumb. And you will probably need a responsive yoyo to get it back in your hand.
Off topic a lil’: I tried doind that once on my M1 and the somhow the nut in the middle was balancing on my thumb and it was balancing perfectly parralel but i never done it ever again after that…
off Topic: i did the same thing with my legacy i balenced my thumb in that little hole of the metal thing but i couldnt get it back to my hand but it was fun