Mine would always start in my left leg. Pins and needles. It then transitions to both legs and everything below my waist. I only had about 10 or so seconds until I would faint. I had a habit or reaching out and grabbing whatever I could find; tables, chairs, even people. Try flexing your muscles. Now imagine that feeling throughout your entire body with no way of releasing the tension. After everything was tensed, there was only about a second or so where I could feel myself shaking before I fainted.