Ryan, there have been several variations of the "quick draw". Some have various snaps and fasteners. Mine, however, are made so that the khuk rides at a 45 degree angle. The sheath is made in such a way that it is totally custom and form fitting (my fit is much better than my finish). The mouth of the sheath is such that it is open from basically the "break" at the spine to the bolster. You sort of slide the khuk in so that the blade is held secure from the tip of the blade to the break in the spine. If balanced correctly, the weight of the handle will keep the edge of the knife against the bottom weld of the sheath, and the top of the sheath will snuggly hold the top of the spine.
The end result, hopefully, is a sheath that allows you to draw the knife by yanking the handle up slightly and pulling the knife free, yet holding the knife fairly firm when the handle is left at rest. Sometimes a nice snap strap is fitted across the back of the sheath mouth to keep the blade from bouncing around and coming unseated.