you were a hashiras apprentice but you were certainly weak, your mentor decided that its a good idea to send you into a forest for 5 days with Gyomei, camping?

you were sitting under a waterfall, the ice cold water dripping down on your bare back, you had removed your shirt before, it was already wet so it was the best option

"Let's close our eyes, little one and calm ourself" Gyomei said, he was sitting beside you, also shirtless even though he was able to take the cold better than you