Riding the centaurs, but not in the way you expect

Once all four ends of slack rope on your harness are ready, the centaur with the bags across his back steps up to you. Now that he is right in front of you, the height difference between the two of you is fully accentuated. Staring up at him, you can barely see his face. The stark difference in size makes you nervous. You are at their mercy, and if wanted to even one of these centaurs could probably kill you by trampling over you. This nervousness is accentuated even more when you feel the slack ends of rope hanging off your shoulders pull you back, tipping you off balance slightly. This drives home in your mind the fact that you are at the centaurs' mercy.

Noticing your nervousness, the older centaur puts his hand on your shoulder from behind and whispers down as close as he can get to your ear. "This will be easier if you just relax," he reassures you.

You nod and take a deep breath, letting him pull you back off your feet. Soon you are hanging in the air, your arms and legs barely brushing the ground as they test the fit and strength of the ropes and knots holding you up. Two centaurs hold you up by the four ends of rope at your shoulders and thighs, easily keeping your entire body weight steady by the strength of their arms alone. To your surprise, the snug harness distributes your weight incredibly well, not pinching in any specific spots or painfully tugging on your skin. Just when you begin to let yourself fully relax and lay fully limp while suspended by your harness, the centaurs gently place you down on the ground. Surprised that you are free to move again, you look around and see the centaurs circling around you. You are about to push yourself up to a seated position when they grab you by the wrists and ankles, tying loops of the slack ropes around each of them. When they finish they lift you up again by the ropes, ensuring that the lengths they tied to your limbs are the proper length. The ropes seem to be a satisfactory length, long enough to pull your arms and legs almost completely straight but not quite, letting all your weight be held by the ropes and not your extremities. The knots are also expertly tied to prevent your wrists and ankles from being constricted by the pressure of the ropes being pulled down by your body weight.

With your harness seemingly completed, the centaurs lay you down on the ground again. With another moment's break, you take another peek towards Siora. She is being suspended stomach-side down as the two centaurs getting her ready test the knots at her wrists and ankles. Satisfied, they lay her back down on the ground as well.

Curious why you both need to be tied up in this manner, you look up to the centaurs standing over you and ask, "Why do we have to be rigged up like this?"

The older centaur takes a step towards you so he can look you in the eyes. "The two of you will be riding one of our company in a way that will not impede their speed."

"What does that mean? Will we not be riding on your backs?" you ask.

"No, we have a better way that will work better for both you and us," he answers. "Strapping you underneath one of us will provide for better range of motion and allow you to be more secure against our bodies. We are almost ready, you will see soon how much you enjoy being tied underneath us."

You nod and take a deep breath, readying yourself to ride in this strange manner.