Knot works nearly as well as Prusik
Knot, but requires only one tuck. It is important to pass
the sling through as shown by the arrows, since the opposite configuration
(passing over at the top arrow and under at the bottom) will cause
the knot to bind. It is also important not to tie the knot upside
down, since its holding power is directional, but climbers often
do so (adding turns to make up for the lost performance). The
resulting knot is the Klemheist.
The performance of any ascending knot depends on the diameter, material, construction, and condition of both the main line and the ascender knot sling material. It may also depend on exactly how one ties the knot. Your knot's performance can easily differ from mine.