an experienced sex move where the woman has her ankles placed behind the ears and the male proceeds to jackhammer at a medium pace. If done incorrectly having the ankle pressure to severe you will break the spine of the female in worst case scenario and/or cause scoliosis.
I performed the invalid on becky and now she walks at 45 degree angle. My ex is in a wheelchair from that very same move last year. You think i would learn.