My friend Badger Johnson wrote an essay on the controversial subject of Trapping :)
Please post a comment on the page for him.
Link below includes links to other great essays by him.
Hope this helps in your Martial Arts Journey, or as I call it, the Sojourn of Septillion Steps :)
http://www.stickgrappler.net/2015/03/badger-johnson-can-trapping-work.html