Page 119 - Geoffrey Budworth, Jason Dalton "The Little Book of Incredibly Useful Knots"

Neck halter

This fixed loop is a quick and simple contrivance to hold a large but docile domestic animal, or

to improvise a neck lanyard for whistle, knife, or stopwatch.

Tie a simple overhand knot at a distance from the end of the rope at least twice the length of the
required loop (1). Add a second overhand knot close to the rope’s end (2). Tuck the knotted end
through the first knot (3) and pull on either side to tighten it (4).