We have two cats one 2year old (Cleo) and a 5 month old (Megara) we’ve had Megara for a month now and they seem to be adjusting just fine, playing, chasing etc etc. Well Megara will go up and groom Cleo when she is either grooming herself or taking a nap, Cleo however does not always enjoy it, she will let it go on for a little bit by then ends up hitting Megara or hissing. Cleo has only licked Megara a few times but only in passing never full on grooming. Will Cleo ever groom Megara, and Why does Cleo get upset when getting groomed? Is this normal? Or aggression ?