Would you like some seemingly stupid advise?
Practice your Kia's in your car, with the windows shut. You are practically sound-proofed. It won't feel as embarrassing as doing this in other places, such as at your home, where you might be self conscience of neighbors or other members of the household hearing. Don't lose your voice, but practice daily until it sounds good enough where you won't feel too self conscience to do it in class. Then, when you practice the Kia in class, do it like you mean it. Everytime. Let it come from deep inside your lungs, not your throat.
When your no longer self conscience, then practice your Kia when you strike an actual target, such as a heavy bag. Then you will get into the essance of what the Kia is actually for. Then you will Kia with the entire body!
Seems stupid, but trust me. :asian: