Jose, I believe a crotch rope is made like this:
1. Tie a rope around the the person's, or your own, waist.
2. Tie a knot in a second rope.
3. Loop the second rope over the first rope in both the back and front, making sure it comes in contact b/w the cheeks, and that the knot is placed strategically on the clitoris (a satin scarf may be best used as the second "rope" for comfort).
4. Tie the second rope in place to maintain contact at all areas.
5. Now, movement and gyrations by the "roped" will cause stimulation in wonderful places. And we all know how to make someone move and gyrate, right?
Everyone please feel free to add something, if I have described this incorrectly. I learned it a long time ago in Boy Scouts, so my memory may be fuzzy.
And Crypt Life, did you say you used this on a friend's AUNT?
Raul