Well, now I'm NOT either a great artist, or an technical engineer, but I guess that you'll grab the point, with a little explanation..*S*
If you imagine a 'digit 8', supplied with a dildo at the center, and a ring at either end.
Now picture this: A nice young female set a foot in either square, and grabs
the 8, upon which she lift it, until the dildo 'disappears' into her vagina.
Next step is, that she get her hands tied to the rings, at the ends, one hand to
either ring, in order to stop her from letting the 8 fall to the floor.
Now the dildo is nicely located, where it does its best, and above that, she's
sort of holding it there, herself. Part of the point is, most certainly, that
she's still able to walk around.