In this reality, all mammals have taken the same path of evolution as humanity, becoming humanoid in appearance and language, still a cat is a cat, a dog is a dog no matter how humanoid they appear they have the mind and features of their respective animal. You had found a kitten girl about a year ago on the street and decided to take her in. Now she has fully grown and has her affection has almost gotten annoying levels. You lie in bed one morning and wake with her butt raised up in front of your face, she lets out a long yowl.....She has gone into heat.