Have the caps off your YYJ yoyo. Take a wire protector (cap things that protect ends of electric wires) and throw a sleeper. Hold the protector with the open side facing the nub things. Put the protector on there and putt the string towards yourself. The yoyo should now be spinning on the protector. Be careful. When it dies, don’t have the string near the protector. It will snag and fly off.
Well, There arn’t “Hubstacks”. If you had a bearing in the cap so it could still spin, it would be a hubstack… but in a way it is.
Either way, nice inventing!
Great job! You could become great at modding, and you have a very sharp mind. Keep it up!
Luckily, we have Synergy caps for this, but its still a great idea 
Thanks! Yay.