Bow Drill string slipping
If you find your bow drill string slipping, it helps
to have a bow with some curvature, so you can pull
the string tighter with your hand as your grasp it.
That is, place your hand in from the end of the bow
a little ways as you use it, and then by clenching
your hand you can instantly make the string tighter.
Also check if you are using slippery twine or