my two year old mix chi/pom kept on nipping at our ankles and feet whenever she gets the chance to. It gets annoying but also painful at times. She doesn't bite, she just jumps around and nips at our ankles or feet. Is this a normal behaviour for dogs? She's actually very friendly and would never bite anyone, it's just she likes to nip at you. Is there a way i can make her stop?[X(]