Let me start off by saying this method will also work for a braid out. I don't know about you but when I used to do twist and braid outs, my ends always ended up either unraveling or keeping my natural curl pattern. It always ended up looking off :/ I came up with this method a long time ago and thought I'd share.
All you need to do is a loose bantu knot and the end of the strands like so:

The result is a nice curly "q" and the end :D

And here is the finished look!