Here is a way to practice proper bow hold using a pencil. While holding the pencil correctly, move your arm as if bowing your violin keeping the pencil pointing at the same point in space, Notice how your wrist flexes to maintain the pencil “aim point”,
I use the pencil drill as one of my “pre-picking up the violin” stretching exercises for my right arm. Do it slowly to feel the stretching and tensioning forearm muscles. If you do it too fast before sufficient stretching there is the possibility of injury.