Any ideas to help stop shoes from sliding off?

Ok ladies I need some ideas...I bought these beautiful 7inch pleaser mules and they are so comfy they have become my new favorite shoes to dance in but they slide off whenever I do inverted stuff. I saw a youtube video with Althea Austin wearing similar shoes and it looked like she tied them on with this clear looking cable. I attached the video below...Anybody have any ideas of what this is or other ideas to keep me from beaning my bf in the head with my shoes when I dance? http://www.youtube.com/user/leighannorsi#p/u/28/ahO4ur5KUUk