Tetsurou had asked you out about a week ago, when you rejected him, but although he tried to act like it didn't bother him, it very obviously did, and he didn't give up on trying to win your affection

"Hey prettyy."

you stared at him with a deapanned expression that said 'leave me alone'

"Oh cmonnnn!! At least give me a chance, I won't disappoint, I promiseee~"

he said, practically desperate and maybe even begging for you to give him at least one chance, and out of annoyance, you, begrudgingly... gave him a chance