I want to say I recall it happening after a turnover coming out of a timeout. I want to say the player the motion was intended for was Josiah Turner. I also want to say Miller mouthed "You. Sit the f*** down." whilst gesturing. But, alas, I couldn't say all those things without an attributable source.
Similar to one of these, but with both hands:

Slim to none chance, I know. But, of anywhere, I figure, this is the best place to ask.