Foxtrot. The person going backwards in this case the lady. The leg is extended to the rear with the ball of the foot skimmimg the floor. The ball will become a toe. Then it will become a ball again at the extent of the stride. Failure to do this will result in the lady rising through the foot, and we don't want foot rise do we.
That took 66 words to explain. Wouldn't it be of some benefit if teachers could explain this early in their teachings.

I would suggest, that those that are competant in their " craft ", have supplied that info. as becomes appropriate .
You,ve described a technique, that many amat. have still not mastered .
When to administer, may vary upon the individuals being taught . Some feel it is the very first thing to drill home-- others, may not . A brief explanation is never out of order .

And-- you are quite correct in your assessment .

Whilst we are on Foxtrot it is worth to Google " Marcus Hilton youtube ". A good lesson can be learnt in his basic Foxtrot . Go to the top one basic Waltz and then find Basic Foxtrot in the list The part I am pointing to is three steps of a Reverse Turn. In particular how on step two he comes right around the lady to back the LOD very square and on two toes. The third step from a balanced position is a step to the rear and is not a prop. For those interested the tune danced to is The Way you look Tonight a none vocal recorded by the Ray Conniff' orchestra from Best of Ballroom Music Part 4. Thats in case somebody likes the music. To study there is a Hover Cross a Check and Weave a Wave and a Fallaway and Slip Pivot into a Change of Direction. For the more daring there is a Throwaway Oversway. Ive manage to copy this to my pictures on my computer by first taking it off the screen with my Digital Camera.