Take a walk, go for a walk.
Run away from your obligations, try to avoid your responsibilities.
- Marcelo, volte já aqui! Nem pense em fugir da raia. Você sujou todo o chão da sala, agora vai já lá limpar tudo!
- Aaahh manhê!
Yup, you guessed right. We use W.O. with the same meaning as in English, especially in soccer matches. When the other team fails to appear, or there isn't enough players in one team, the other team is considered the winner by W.O. (or vencedor por W.O.).
And although most Brazilians know what is a W.O., they have no idea that it means Walk Over.
- Quem venceu o jogo ontem?
- O São Bento venceu por W.O. do Juventus.
Pull your weight.
Run away from something or somewhere.
- Dá no pé que os cara chegou!
- Dia bom pra ficar na cama o dia todo né? Dia chuvoso...
There are jokes on this too, because cofrinho is also how we call piggy banks. So when someone sleeps on his chair and you spot his/her cofrinho, some people drop coins in there.
You can either say "mostrar o cofrinho" (show the buttcrack), or "pagar cofrinho" (pay? buttcrack). Both expressions mean that you are displaying your buttcrack.
Shortened version of "bocadinho", that is the same as modicum, or just a little bit.