If you are having to teach a "scoot closer" cue, it means you haven't taught the ready or the heel properly in the first place. Sorry, this is a pet peeve of mine.
Can't ask a dog to scoot closer at a trial now, can you?
Are you familiar with "doodling"? It's a fun game of the dog finding the heel position as you move from place to place. Keep it fun, use a great motivator and teach the dog what heel really means. Then you don't need a second cue.
Make sure you are only rewarding for close and straight. It may be that the dog has been rewarded or released for wide and crooked enough times that it's causing some confusion.