Looking for a yaoi manga

It’s a one-shot manga but I can’t find it in the one-shot section. The story goes by where there’s a man who’s actually a beast (maybe werewolf), he makes medicines, rescued a little boy(beggar). The little boy stayed and learnt a lot from the man. During full moon, the man would make a lot of food for himself and lock himself in his room, also warned the boy not to enter no matter what. But the boy entered the man’s room and they did it. The next morning, the boy woked up and hugged the man, the end. If I’m not mistaken, this manga is associated with shouta