He hadn't even had time to think before the first blow slammed into his arm. The pain was blinding, and while Gwen was still talking- yelling, actually- he couldn't really understand what she was saying anymore. He tried to back away, but the bat hit him again, knocking him to the ground.
In pain, Stan tried to grope for his wand, but she'd hit his right arm, and he was clumsy with his left hand even at good times. Considering how clouded he was with pain, this was not a good time. His fingers scrabbled against his cloth-covered wood as his own robe blocked him. Stan kicked weakly with his legs and pulled at the trapped wand.