Otto is about a year and a half old, min pin/dachshund mix. I've had him for about 6 months, and he's always gotten along great with my cat, Khepri, who's a 2 year old sphinx cat. When we got Otto, he was very underweight, and he and the cat were pretty evenly matched in their playing. Also, he was much more timid. But now that he's put on a few much needed pounds, and gained some confidence, he kinda bowls the poor cat over. I can tell he's just playing, and half the time the cat starts it, but he doesn't seem to realize when the cat is done. It used to be that when the cat got tired of playing, he would swat Otto a good one in the head (never with claws), and Otto would back off, do a play bow, and wait to see if the cat walked away or pounced on him. But lately Otto seems to get so excited, he just doesn't stop. I can probably get video if that would help. The cat will start making a ruckus, and I will either call the dog to give Khepri a chance to run away (half the basement and the entire second floor are cat only zones), or I walk in and scoop Khepri up into my lap. But if I'm not home, I can't do that. I don't want to separate them, because they sleep together, groom each other, and really do get along, it's just that Otto doesn't know when to back off anymore, and I don't know how to teach him... Help?