Whippings Overview
Introduction
Whipping is my preferred approach to finishing rope ends. In this context a whipping means twine/thread wrapped around the end of a rope. The great advantage of whippings is that they don't catch at all when pulling your rope through.
I usually order ropes with unfinished ends or simple end knots, and whip all my ropes with the same thread, which makes them easily recognizable as mine (this can be valuable in group settings where everyone has similar-looking rope). Some people like to color-code their whippings to indicate the length of the rope.
What to Whip With
The most traditional material for whipping is waxed natural-fiber twine. I've never tried it. It probably holds better, but bondage rope is not subject to that much abuse, and honestly your choice of material probably doesn't matter much.
For a long time, I've been using Gutermann Top Stitch Heavy Duty Thread, which is a strong polyester thread. It's about the thinnest thing you'd probably want; any less strong, and it would break too easily to tighten the whippings down well. I also double it up while whipping (i.e. I place the needle at the halfway point of the piece of thread); I just find it easier, and it adds some strength.
Obviously if you choose a whipping twine too thick for the rope you're whipping, it will be hard to work with, and the final whipping will be bulky.
Types of Whipping
The gold-standard whipping is the Sailmaker's Whipping; it has stood the test of centuries of seamanship, and is exceptionally secure. It does require a fair bit of tedious needle-work.
My preferred compromise is what I call the Quick Sailmaker's Whipping; it still requires a needle, but is much faster and easier on the hands to perform. If tied well, it is secure enough to survive several years of regular use, longer than many bondage ropes will last anyway.
A quick option that doesn't require a needle is the Common Whipping; I don't recommend that for long-term use, but it's a good temporary fixture, and can be used to practice the basics of whipping.