you snooze, you lose; someone who is inattentive misses the chance or gets left behind
Envie a inscrição hoje: camarão que dorme, a onda leva.
Submit the application today: you snooze, you lose.
The image warns that a sleeping shrimp is helpless before the current: someone inattentive or slow to act can lose an opportunity and be left behind. The wording became nationally familiar through samba.
Falando's Idiom Trainer teaches you to recognize idiom meanings and create sentences using them, so you can speak like a Brazilian.