Practice again is the only thing that can teach this.
"Now you have the whole theory of throwing a rope.
"There are four sorts of throws, but they are all made alike, only the position of the arm being different.

They are the overthrow, the underthrow, the sidethrow, and the backthrow." "Backthrow ?" "Yes, backthrow--catching an object behind you--something that you need not even see.

That sounds difficult, does it?
Well, you stand behind me and you can see it done." The reporter took his station twenty feet behind Mr.Ohnimus, quite out of sight, of course.

He swung the loop around his head, and, without turning, let it fly backward.

It circled the newspaper man exactly, and by pulling it quickly Ohnimus had his arms pinioned to his side.
"Are there any more trick throws ?" asked the reporter.
"Lots of them.