When you need a quick and convenient temporary knot that can bear a continuous load and be rapidly untied, even under load, think of a toggle knot.
To produce a toggled reef knot, any fixed loops will do, but the loops ends must be secure. This knot is ideal for joining two eye splices, the loops of loop-producing knots or any combination of loops.
A. Bringing two loops together from opposite directions, take the tip of one loop under and through the tip of a second loop. Press the legs of the second loop up through the first loop and hold them in position.
B. Place the toggle between the legs of the second loop in front and the legs of the first loop behind.
C. Draw up tightly and maintain constant pressure on the toggle.
Original materials used with thanks to Irene Rodriguez and John Bennett