H-mehtod.

The H-method have, like the two other 'letter-methods' gotten its name from the way the rope lay on the wrists, but it's hard to show it, as the horizontal bar in the 'H' is between the wrists, and thus difficult to photograph.
The H-metod divides itself from the x- and the U-method, by being good for tying up parallel items, like i.e. an arm on an armrest.

1/ Bend the rope at the middle, and make a loop.
Put this loop around your partners wrists - not too tight - that'll come later.

2/ Make 3-4 turns around your partners wrists    -the right way around them.
Pull the ropes through the loop you started out with.

3/ Pull the ropes either way around the turns, between your partners arms, tighten the whole bondage by pulling the ropes, and lock the bondage with a reefers knot        -you may hide the reefers knot between your partners wrists, if your partner's the one who tries to get free..!