There are many variations of Hip Harnesses.  Here is one by MrLeto.

I like the way he weaves his rope around his model/bottom.  This spreads out the rope contact over a relatively larger area, making it more comfortable when put under suspension tension.  This harness offers multiple ways to attach support lines for different types of suspensions.

His tutorial video is included after the break.

The picture at the top of this post shows the criss cross ropes on the the front of the hips.  Here is a picture of his harness after he moved the criss cross ropes to the side of the hips.  

You can see a shibari presentation which includes this hip harness here.