Why do you get a tingling sensation in your thighs after exercise?

Your thighs usually feel tingly, like Jell-O, because they are out of oxygen. With the oxygen being constantly used, your muscles are fermenting (hence why they feel like Jell-o), in order to produce more oxygen when they've ran out of the normal source (the CO2 you breath, being turned into oxygen). It's perfectly normal to feel this, it just means you should rest for a little bit before continuing your workout. :)