Use your right knee to block the view from first base, your glove will block third - keep the glove forearm relaxed so the wrist is down, and rest it on the knee, glove hanging over. Signalling hand should be tucked in tight to the cup - so it isn't down below the thighs. Keep the chest vertical, don't slouch. Present a flat target with the wrist pulled back, fingers up. Keep the bare hand back behind the body, out of harm's way.
Upper body needs to stay loose for sideways lean to get square to the pitch.
Frame pitches only when close and always with the ball inside - see more on Selling Strikes . Set up with the knees out, feet flat, but keep the weight inside for leverage. To get into this position from the sign-giving stance, try to do it with a two foot hop. Blocking balls in the dirt is easier from this stance. See No Passed Balls for details.