It was loud, even in his room it was loud. Denki and Sero were messing about in the common room and Katsuki didn't want to risk getting a headache with finals just around the corner. So he switched his hearing aids off to study, not thinking to mention it to you. Which was all well and good until you needed his help with a question and tapped his shoulder to get his attention, making him almost him jump out of his skin.

"Hey!" Katsuki flinches in surprise and raises his voice louder than meaning to, scowling as he moves to switch the hearing aids back on. "What are you playing at?! Making me jump like that... idiot. What? What do you need?"