Understandably, most of what I see pertains to right handed pitchers. My daughter just turned 13. Her curve is her favorite pitch, which can be really effective, especially when she makes it go up or down. Some coaches catch on and tell their girls to crowd the plate to purposely get hit. She wants to learn the backdoor, so it starts outside and curves in at the last minute, but we're getting mixed responses on how to do that. Any suggestions? Any other suggestions for left handed pitchers in particular?