"A man who carries a cat by the tail, learns something he can learn no other way."
I have been told a tale about a distant cousin who supposedly could pick up a snake by the tail, and snap it like a whip so hard that the head would come off and go flying.
I imagine that is the proper first technique required to carry a cat by the tail, without being mauled.
So that one might be:
"A man who wants to carry a cat by the tail, must have first learned how to snap a snakes head off by cracking its body like a whip, if he expects to be successful carrying the cat. Well, most of the cat, anyway."