By the time you realize you're thirsty, it's already too late.

In high school, there was a girl I dated just for fun and then dumped. After entering university, while playing around with a friend, I happened to see that girl. There was an unfamiliar man next to her. --Ah, it was at that moment that I realized it. ※Please be advised that the protagonist displays uncomfortable behavior and remarks toward a girl, so those who find such content disagreeable are advised to refrain from reading.