He was on a roll with the answers that day and didn't want to stop.
He was the one who switched the bones, killing two stones with one bird—" "I think you've got that a bit mixed up," Dean offered, but Fred was on a roll.
Dean continued to feel miserable but Fred was on a roll.
Fred was on a roll as Dean knew he'd be.
You're on a roll.
The steady mass, however, is much larger, being too kilos (or 220 Ib); the magnification is from 80 to loo; and the registration is effected on a roll of smoked paper.