I see a lot of videos and images where people are being suspended just from the chest or legs, but with bondage like that, where the appearance is the top priority, the bound one needs to be physically strong, or else it'll end up being pretty painful.
In order to suspend in a less demanding manner, you can bind the waist with rope as well. There are two different ways to do this.
The first is to tie rope around the stomach, and the second is around the pelvis.
When rope is tied around the stomach, it could end up causing pain depending on what sort of position the bound one is in. (Facing up or down, etc.)
Additionally, the rope digging into the flesh around the stomach can cause some people to get sick, so I don't really recommend it.
(Of course, everyone is different, and some people prefer the stomach.)
Tying rope around the pelvis can also cause pain depending on the position of the body, and if you aren't careful, it can end up causing severe pain,
so I'll explain how to do it in detail here.
(Everyone's pelvic bone is different, so always make sure to check the position.)
In the below picture, I'm pointing to what is the top part of the pelvis. (Which touches the stomach)
In the below picture, my thumb is on the protruding part of the pelvis. (If you apply rope here, it'll hurt.)
In this picture, I'm pointing to the sunken-in part of the pelvis. This is where you should apply rope.
(Large people may feel pain when the rope is tied tightly. If they do, be sure to loosen it.)
This step is instrumental in keeping the rope from slipping up to the stomach.
Slide your arm through the legs (so that your arm is pressed up against the crotch) and then pull the rope through.
If you let the rope sag, or grab it too low, it will make the rope wrap around a lower point than intended, so please be careful.
Pull your arm back under the crotch and wrap the rope around and up the inguinal region, like in the picture below. If you wrap the rope any higher than this, it will end up overlapping a region that has ligaments and lymph nodes, so please be careful.
Likewise, if the rope falls too low, it'll hurt, so you really need to be careful.
When suspending upside down using only the waist rope, you may worry about the waist rope slipping. (Especially you're suspending a man, or someone heavy.)
In these situations, you can tie the stomach as well as the waist for additional support when suspending up-side down.
You can also use the back for support when suspending upside-down, instead of just the stomach. (Which means suspending the bound one face-up before going upside-down.)
This method can also be used when suspending face-up using only the waist.