Want a fun exercise for helping your students go more deeply into twists? Have a partner run her finger up the student’s spine while the student is in a twist. We have a tendency to twist in the same part of our spine every time we twist. (It is usually around your lower ribs at T11 and T12 and L1.) We can twist in other parts of the spine, though, it just take finding them.
When someone takes her finger up your spine, you are able to “feel” more spots where you can turn more deeply. If you have chairs, do the twist in the chair. If you don’t, I find Maricyasana I to be the easiest pose to do this exercise in.
Have the student come into whatever twist she is doing. (Since you are already using partners, have the partner put her hand on the student’s head so she thinks about lengthening as she moves into the pose.) Once she is in the deepest twist she can get into, have the partner take a finger to her lower back, just above the sacrum, and slowly slide the finger up her spine, vertebra by vertebra.
Have the partner go slowly enough that the student can integrate the touch and see if she has access to any twist there. Be sure to do both sides. Your students will be absolutely amazed at how much more deeply they are able to go.
This exercise is fun even with beginners. Most people get a sense of going deeper in the pose. Enjoy!