Mount your horse and let the calf get ahead of you. Once you begin chasing after the calf, it will run away. Keep your horse at a canter or gallop, depending on how fast the calf is moving. Ride up to the calf on one side, just slightly behind so you can aim.
Spin your lasso over your head in a clockwise motion using your wrist to control the diameter of the spin, which should be about 8-12 inches. Create the spin as if you are continually drawing a circle over your had.
Point your index finger to aim as you throw, pointing it toward the calf, aimed at your imaginary target just in front of the calf. Toss the rope underhanded, aiming just in front of the calf. This prevents a short throw because the calf is likely to run into the lasso.
Yank on the rope when it is around the calf's neck. This will pull your slipknot tight. Dismount your horse beside the calf and wrap your arms around the calf to pull its feet from beneath it, pinning the animal to the ground.
Pull your piggy string from your belt. This is a rope of about 30 inches. Weave it around the calf's legs, beginning with the front and working toward the back, alternating direction, as if you are weaving a loom. Do the looping pattern three times to ensure the calf's legs are secure.