The end of the year, the day of the sacrifice to the dragon. The time where everyone gathered all their expenses and left it in a spot for the dragon to collect

Being stupid enough to get your ankle caught in some wire when you were leaving your own gift made Falkor think you were apart of the sacrifice and took you

The problem is he was stubborn, not up for listening or negotiating thinking you were put there purposely for him to take as he ignored your attempts to explain, not caring