NFL mechanic question
 

I don't work football, but am always intrigued by signals/mechanics among crews.

Can someone tell me what it means when the R (NFL) waves his hands in front of his body in an up and down motion and then points towards the offensive line? At first, I thought it had to do with a player in an 'irregular' number reporting as an eligible receiver, but then I looked at the o-line, and didn't see any irregular numbers on the end of the line.

I saw this happen over the weekend and it's always puzzled me - appreciate the feedback.

When did this action occur, and were the hands moving together or opposite? Was the ball ready for play or being readied for play? Or in play?

R's hands were moving together, up and down in front of his chest; ball was ready for play and o-line was settling into their stance.

Complete guess:
A lineman had his shirt untucked and R was asking for help getting it tucked in after the play.