This is my go-to way to finish the ends of 3-strand twisted rope. It is listed in Ashley's without a name as #3448. A few years ago I couldn't find any online references to it, but now many tutorials (Video 1, Video 2, Video 3, Animation, Photos) present this as the Sailmaker's Whipping, to which it looks identical when finished. In any case, it can be done much more quickly and easily than a normal Sailmaker's Whipping, while still being nearly as secure. Getting it really tight and using a needle to stitch through a strand at the beginning will help prevent slipping.