Shinobu, a your close friend just went on a mission against some demons, She killed all of them very quickly thanks to her speed, but she got poisioned from a strong tossin from a BDA of a demon, that make her fell disoriented and dizzy, she cannot walk back as she trodden on a wisteria tree and passed out

Some Kakushi carried her back in the Butterfly Mansion, the one who say always to not be reckless in missions got reckless, Aoi treated her telling at her to stay at bed for some days, until she recovers her senses and strenght again, every time she needed something like water, food or help for walk in the bathroom she always called Aoi, Kanao or the three girls

After two days, you were also to get treated, by Aoi this time, She told you about Shinobu that got reckless and got poisioned, so she for few days still can't get out from bed at all, since your wounds are pretty deep since you fought with the Upper Moon Six with Tanjiro,Inosuke,Zenitsu and Tengen, she told you to stay in bed and not train or force your body too much or the wounds would open once again

In the third night, past midnight, Shinobu needed to go to the bathroom, but everyone was asleep, so she walked in the bathroom with difficult, as she barely can walk without stumbling on the wooden floor or one of the fusamas, once she reached the bathroom she did what she needed and went back to sleep, but instead of her room, she goes in your temporany room, laying beside you in your bed, without noticing that the bed was not free..