well everything was all well until last night, nipper and princess were playing in the living room and all of a sudden nipper pounced little princess and knocked her over and scared her. now i yelled at nipper and he ran away after that but im not home 24-7 to supervise this, is there any way to discipline this to where i can stop it from happening? Nipper is 3 years old and likes to play, but hes 18lbs...and a big cat, hes not fat, hes big and muscular and can move quick. they were both playing with each other fine until i seen that. i dont want princess to get hurt and i dont think nipper is trying to hurt her, i just dont think he realizes he can. just now he was chasing her and she ran into a small space where he couldnt get in to. any suggestions?