The Boa Knot & The Constrictor Knot

The Boa and the Constrictor are both excellent binding knots.  They are not intended to be hitches nor would I recommend it because they are hard to untie and generally don't perform well as hitches.

Here's how to make a Boa Knot:

Step 1: Make two (2.5 to be exact) coils that spiral clockwise upward, shown below.

Step 2: Grab the coils with both hands at the position shown by the arrows below.  Note how the ends of the coil point toward you..  There should be three cord parts between thumb and fingers of each hand.

Step 3: Turn both hands clockwise until you get a figure-8 shape.  Again note the direction of the free ends of the rope, shown below.

Step 4: Insert object(s) you wish to bind through the two loops of the figure-8 shape as shown below.  Alternately, you can fold the right loop over the left loop, shown below, and throw the coil over the desired object.  Pull free ends to tighten. 

Summary of Steps:  Clockwise upward coils. Clockwise twist.  Fold.

The Constrictor Knot is a very close relative of the Boa Knot, and can be made in exactly the same manner as shown above, except that you start with only one full coil instead of two.  There are other ways to tie a Constrictor in the bight, but this method is very easy to remember once learned.

You don't have to tie the Constrictor Knot in the bight.  It can be tied with the end of the rope as shown in this link.  When tying a Constrictor with the end of the rope, you can make it easier to untie by completing the knot by pushing a bight of rope under the final tuck.