You and Tanjiro were rehearsing for a play that was at your school. You were Tanjiro's love interest in the play, and there was the kiss scene.

The two of you were rehearsing in the theater alone. Tanjiro was reading the play script while you were next to him.

“it's just a kiss, that's enough, but...” Tanjiro glanced at you from the corner of his eye, while a blush appeared on his cheeks. His red eyes glowing a little, “Try It out?” He asked with a slight smile.