i wondered the same thing to and it was hard to find but i looked it up snd its called The Bonus Meter. The Bonus Meter adds points for daubed numbers and slingos and the higher the bonus meter is the more points are added. And Daubing Numbers And Getting Slingos Makes the bar go higher. The Longer you wait between Daubs the farther it will fall. The bonus meter does not fall when the spin button is active.