on the hoof
1. (British & Australian) if you make a decision on the hoof, you make it quickly to react to a situation which is happening, and do not have time to think about it carefully I don't want to make a decision on the hoof -- I need to give this some thought.
2. (British & Australian) if you do something on the hoof, you do it while you are walking around doing other things He's so busy, he usually has lunch on the hoof.