The X-method.

The X-method derives its name from the X-shaped way the rope is applied to the arms.
It's a brilliant way to bind things together, as long as they are not parallel.

1/ Lay the rope diagonally over the wrists. Pull the ends down under the wrists, cross them and pull them up again. 

2/  Now continue that, until you've got 3-4 rope-lines next to one another. 
Cross the ropes, and pull them either way around the bondage between the arms. This will tighten the bondage, and when you give the ropes a little tug, it will lock.

3/ Finally you tie a reefers knot to end the bondage, obviously in a place where your partner cannot get at it !