Mucky baby

Busy busy day, had my hair done at my friends house today then another friend came over to mine for a cuppa.
When my friend was here I was saying to her how happy I am with Lola's behaviour and literally five minutes later she bit her son really nastily right on his cheek !!!! I was so happy with Lola because she hadn't bitten for ages and then bam !! Luckily it was my best friends child and she was really good about it !but oh my god it's literally driving me mental !