Observation Handbook of Non-Human Love

[Two male protagonists + non-human + unit text] What should I do if my love partner doesn't seem to be human, but actually smells good? Cats can hide their tails and dogs can do housework. Someone picked up a puppy covered in scars on a thunderstorm night. Unexpectedly, he woke up the next day and turned into a husband-like boyfriend who cooks, does laundry, and even picks you up from the social den. Someone suspected that his roommate was a cat demon, so he launched a meticulous love-style "investigation". In the end, he failed to catch the cat by the tail. Instead, he was pounced on. "You said you're not human?" "That's okay. I only like you anyway." This is an observation manual that is not too serious but very serious about falling in love. There are tails, claws, and eyes slowly approaching you—— Also, the one who quietly appeared next to you on the day you were loneliest Bit.