This is a term that is new to me. There doesn't seem to be a listing in the Glossary above, and the search function only returned three matches, none of which involved a description of the exercise.
They are a type of snake that crushes their prey. Good examples are the Anaconda, Python, and Boa Constrictor. They are also the longest and thickest types of snakes around.
Indeed, between Red, Supra and Still so many exercises, tools and advancements happened! We have more exercises here than all other sites combined, and then some. This forum has always been about innovation, being on the cutting edge of PE, delivering new and more powerful tools and exercises than anyone.