The inside endo starts with the gymnast beginning to pike as the body is already bailing over, and keeping the shoulder angle as open as possible while the pike compression increases. Aiming to get the feet between the arms and the rail cleared before the hips, the center of mass moves down lower than a horizontal line with the bar.
The gymnast demonstrating this combination bails over with a little arch to begin the inside endo, but then shows a good compression, and on the swing up and comes out of the skill with the correct hip roll-out action. On the pirouette to mixed grip he again has a slight arch that could be refined to a straighter position and keeps his head slightly out to maintain visual contact with the rail during his pirouette which helps him to regrasp the bar more consistently.
In general, one of the most common learning mistakes of either straddle or inside endo to full pirouette is to swing down crooked after the pirouette. The reason for this mistake is an excess of support transfer to the post arm. The gymnasts shift their weight like they were going to perform the regular front pirouette that they have learned before, and that really requires a support transfer beyond the vertical of the post arm to finish square in a different bar position.
As mentioned before for the endo to mixed grip full pirouette combination, some of the gymnasts' main goals are to clear the rail, to flow from the endo to the pirouette without a large pause, and to swing down square. Notice how the gymnast keeps his eyes on the bar during the full pirouette.
Back hip circles begin from a regular cast when the gymnast leans the shoulder back off support. When the body is coming back to the bar, but before it makes contact, the gymnast's aim is to complete the skill with a straight or hollow body that moves around in a single unit.
Gymnasts begin learning back hip circles from a small cast. Right when their bodies start coming back down to the support, the coach standing on the opposite side of the bar, reaches with his arms under the rail and places one hand on the lower back and the other on the hamstring area. The hand that was on the lower back then reaches under the bar to stop the gymnast from "over rotating" the skill.
It is very important to understand the dynamic nature of spotting any gymnastics skill. The spotting patterns must be adapted to what happens on each individual attempt. the coach must be ready to move his hands to different areas according to the occurrences of each situation.
Gymnasts having problems with leaning the shoulders back out of support and turning over in one body unit for under-shoot dismounts, may benefit from learning how to make a complete back hip circle without having any momentum from a cast.
"Throwing the head out" is a very common mistake that does not add any technical or presentational value to this skill.