Question: “Is it proper technique or a result of competition to leave the last couple of feet of your rope on the left side of your horse? Most roping coaches teach this but can’t explain why.”

Answer: “I guess the question would be, what happens if you don’t? And the answer is the tail of your rope could get tangled in your coils and create a knot as you slip dallies, or it could get tangled in your dallies.

I like to have the tail of my rope lower than the withers when my left hand is as high as it’s going to be to rein my horse with my coils well above the saddle horn out of the way of my dallies.
You don’t have to be around inexperienced ropers very much to learn why you don’t do some of the things grandpa told you not to do.
Good luck,
Martin Black