Joe-joe, I’ve been working on the “stretchy chewey” for a long time, and I think I can explain it.
It is a trst to see if your horse is truly on the bit, and you should have contact even though your reins are longer.
The goal is to get the horse to stretch his neck down and out, which is a super important part.
Start out with a nice elastic contact, and let out the reins a bit, and your horse should REACH for the contact. Establish contact on the longer rein, and let it out a bit more, and eventually work up to the point where
I would try this at the walk (freewalk) before trying at the trot.
The point is to show that your horse is truly on the bit. If he is on the bit correctly, he WILL stretch! A lot of people run into problems when they have the horse behind the bit, and the horse falls on his fac ein the freewalk.
The picture below is a super correct example of the freewalk.
"Think of riding as a science, but love it as an art" ~George Morris