to drop the ball, to let someone down
Esqueci nosso aniversário de casamento, sei que pisei na bola.
I forgot our wedding anniversary, I know I dropped the ball.
The expression pisar na bola (literally "to step on the ball") comes from the language of football. A player who carelessly steps on the ball loses control of the play, stumbles, or gives possession away, committing exactly the kind of clumsy slip that lets the team down.
Falando's Idiom Trainer teaches you to recognize idiom meanings and create sentences using them, so you can speak like a Brazilian.
