My rescue dog ( she's about a year old now and has been with us 4 months) sometimes bites really hard when she is playing with me. At first the gentle nips or mouthing were harmless so I didn't mind, but now, when she gets very excited, rolling on the sofa or on my lap, she bites hard! I have been telling her "No bite" and stop playing with her for a moment -- perhaps I should put her on the floor or walk away? She's so cute I can't resist when she wants to play.