There is actually a very simple and highly effective way to do this, without the need for any attachment points on the hotel bed.
Get a wide cargo strap with a ratchet mechanism on one end from a hardware store like Harbor Freight. The best ones are made for heavy truck loads and feature a 1 1/2" wide strap about 15 feet long.
Have your patient sit on the edge of the bed and lean as far forward as possible, putting her head between her knees.
Position the ratchet on the distal end of the thigh, that is the end closest to you as you sit facing the patient. Place it at the outside of the thigh, right above the knee. Now, take the strap under the thigh, around the patient's back, a few inches under her armpit, across her back to the opposite side. Go back under the opposite armpit to the inside of the patient's opposite thigh, around under it just behind the knee, and then back again across her back.
Finally, take the strap under her armpit back to the ratchet where you began.
Put the strap into the ratchet. pull snug and ratchet until nice and tight.
You are now ready to grab the patient's ankles, just like wheelbarrow handles, and lean her back onto the bed.
Put your arms round the patient's thighs as she lays on her back and pull her buttocks to the edge of the bed.
The knees of the patient will be held back tightly against her body and held well apart just to the right and left of her breasts. Both the vagina and the anus will be in clear view with full and will be completely unobstructed.
She will be completely exposed and vulnerable, with her vagina gaping open.
You can get these cargo straps at Harbor Freight for about $15 each.
For further information feel free to contact me.