There are a few variations of Boomerang on the mat out there. In fact, in my Youtube video you will see one variation and in my online mat classes, I teach a whole other variation. I am not here to say what is right or wrong. But, I will say the one I teach in my mat classes I do love a whole lot more. So, I'll describe it below. And, if you have questions you can ask me! Just remember, this is a rolling exercise. Stopping to do all these other thins takes the rolling out of it.
Hug your legs together from your outer hips and upper inner thighs.
Boomerang usually comes after Seal and Crab and before Rocking. You are in the mats grand finale and getting ready to stand up! So, sitting up, cross one ankle on top of the other. Squeeze your legs together and pull your stomach in. Round forward over your legs and then without changing the shape of your body lift your legs to you. Rock back, switch the cross of the legs and as you round forward press your hands back like rowing and control your descent. Pumping your arms up 3x as you maintain your shape and lower down. Repeat 3-4 more times for a total of 2-3 sets.
Boomerang looks like a bad beast of an exercise but it is simply your Roll-up meeting your Open Leg Rocker being challenged by your Teaser with a little Seal and Crab and then finally using the back connection you learned in your Double Leg Kick and Hip Circles. Sure, this is not the first rolling exercise you will get and it may even be the last one you try but it's not something you cannot do. If you can do most of the exercises listed above add this in!