I have an overweight male kitty who's about 28 pounds (he's dieting under veterinarian's constant supervision) and my roommate has a small 9-month old female kitten that's probably under 10 pounds. They've been best of friends for many months, since the day the kitten first entered the household. They sleep together and groom each other often. Both cats are fixed. The female kitten is extremely vocal and walks around talking constantly. Lately, my large cat has begun trying to pin the little kitten down, biting her and using his weight in an attempt to immobilize her. The kitten fights back, vocalizing loudly and wiggling. It freaks my roommate out because she thinks my big cat is hurting the little one. However, whenever I see them doing this, I walk over and insert my fingers into the area my cat is biting; he's not breaking the kitten's skin and is actually applying very little pressure. The only thing the kitten ends up with is a bit of wet fur. Also, the kitten sounds peeved, but not in any pain, and she keeps coming back for more. Should I be concerned? Should I be reprimanding my cat? I don't want to be mean to my guy if they're just tussling. Any ideas?