So me and my boyfriend was having sex and I asked him to tie me up the only thing we could fine was some really long shoe laces so he tied them around my wrists after about 20 minutes he stopped and was frantically taking the shoe laces off my wrists and said that my hands had gone blue and looked numb. But I was really enjoying it and wanted them back on but he wouldn’t. Just wondering what it means when your hands turn blue and what the side effects would be if it happened again in future and we just carried on without untieing it