At some time or another, most obedience competitors will struggle with straight fronts, back feet that stick out to the sides ( rabbit feet), dogs that are not able to "find front" from an angle, and rock back sits. As a general rule, I try to work young dogs on small, tight platforms to help them develop muscle memory to prevent these issues.  While this does not teach a dog to think about being straight, it does create muscle memory, which can make the process faster and easier for the dog. But eventually, I want to get rid of the platform for routine training, and a nice middle step is to teach a dog to stay between your legs.  If you are using this position to help the dog learn to keep their body straight and their head upright, then a sit is not required when you stop.  If you are using this position to teach a tuck sit with all four feet pulled in tightly, then expect (or ask for) a sit before reinforcing and possibly rotate between sit and stand.  If you are using this position to teach your dog to keep a straight body no matter how you pivot, then rotate as much as 360 degrees in both directions.  If you are using this position to teach backing in a straight line, then start with one step at a time and slide your feet straight backwards. This exercise can also be done while holding a dumbbell or a glove, since some dogs only sit crooked when they are retrieving.  And since rocking back between your legs is pretty much impossible while holding a dumbbell, your dog will tuck sit.  Do enough repetitions and a tuck sit while "in front" will become a habit, giving you a chance to reinforce the ones you like. As your dog becomes more competent, you can stand up straighter and reinforce only occasionally. The following video is of Raika - we're working on tuck sits/kick back stands, and pivots/keeping her body straight.  Raika is "trained" so she'll stay in this position comfortably no matter what I do.  If you think about it, if she tried to rock back on a sit she would 'disappear' from between my legs - and away from the cookie.  She doesn't want that so she tucks nicely.  Same with the stand position - she knows where the cookie is going to show up, so it's easiest for her to hold her front feet still and move her rear. And this video is of Brito - we're using this position for his "rabbit feet", to straighten his fronts, and soon I'll use this position to practice his dumbbell hold.  He is not experienced with this position so I have to work a little harder to keep him there. Notice that even though both dogs are very different in size, their back feet still come up between my feet and meet with their front feet.  If your dog can sit this way, then you can use this exercise effectively for all of these exercises.