What did Maniac Magee need to have in his hands when he was listening to Grayson's stories?

From the text:

It was impossible to listen to such stories empty handed. As soon as Grayson
started one, Maniac would reach into one of the equipment bags and pull out a ball or a bat or a catcher's mitt. Sniffing the scuffed horsehide aroma of the ball, rippling the fingertips over the red stitching — it's hard to say how these things can make the listening better, but they do, and, for Maniac, they did.