What is "bottle sling"

n. A knot that can be used to create a handle for a glass or ceramic container with a slippery narrow neck.

The bottle sling (or jug sling) is a knot which can be used to create a handle for a glass or ceramic container with a slippery narrow neck, as long as the neck widens slightly near the top.

While classed with binding knots, such as the reef knot and miller's knot, the bottle sling is able to perform a function for which most other binding knots are unsuited. The bottle sling's specific form allows it to grip a cylinder, assuming it has even a slight flare or collar, and lift it along its axis when the knot is loaded by all four strands. With appropriate size cord, most wine bottles can be reliably suspended with this knot.