Ever wake up in the middle of the night because your calf muscles started seizing on you? It's a really painful and stretching or flexing the leg only intensifies the pain.
Here's my tip for getting rid of a Charley Horse that works for me immediately, every time. Stand up. Yup, that's it. As soon as you wake up from a Charley Horse, DO NOT flex or stretch your leg, but instead, just get out of bed and plant your two feet on the floor. IMMEDIATELY the pain will subside. The calf will still feel tight, but you'll feel instant relief.