10 week old working cocker puppy. She’s feisty and has nipped before (I yelp and then turn away and refuse to interact). But generally she’s loving and gentle.
Today she was playing in the garden with my son, running around. I was watching and he wasn’t teasing her. It’s a game they have played lots.
Suddenly she lept up and bit him on the crotch. It’s a proper hard bite, she has left two bloody and bruised teeth marks.
He screamed. I shouted at her, clapped my hands and shouted at her to sit. She kept trying to bite him and I had to pull her off. She’s now in her crate.
Please help! How do I make sure this never ever happens again?