So I was watching a video and saw a boing-e done with one hand. They had two identical yoyos, one that didn’t spin or have a string. They stuck the unspinning yoyo in place of their left hand and did their boing-e. so I thought about wether or not you could do any other tricks with that setup. You probably could, but you would need something that wouldn’t fall off a string.
I believe he means the yoyo was at the bottom of the string but not attached to act as a weight rather than your left finger, then doing the motions with your right hand as usual
It’s been done since 2000 at least… there was a short era of dead-yoyo-as-a-counterweight tricks… not a whole lot came from it, but that one was pretty cool.
I actually teach this as a method to learn boingy-boing since the weight of the dead yoyo hanging at the bottom of the formation puts just enough tension on the string, that the throwhand can just focus on the up and down motion to get the boingy-boing to work.
The easiest way is just to have the spare yoyo in your non-throw-hand and just use the gap of it like it were your index finger. (similar to mounting blueline rolls for 3a)
Then, once the spare yoyo is hanging at the bottom of the formation, just let go of it and do your thing.