This expression means that it is not easy, that it is complicated. "Tá" is a informal abbreviation for the correct verb conjugation "está", and "foda" could be translated to hard, or fucked.
Used to describe that something is not easy. It could be a relationship, your job, the car maintenance, etc.
- Como vai a vida Seu João?
- Tá foda. Não pára de aparecer problema.
Slang, for "meu irmão", which would translate to "my bro". You can use with other lads. Women rarely use, as it would sound as they were trying to portray a man, or being sarcastic, etc. Never use it in formal situations.
- Coé mermão! Como você entra sem bater na porta?
- Opa mermão! Como vai a vida mansa?
- Ah, sempre de boa né?
There are two means (or more):
1) When you are doing (or will do) something boring, it is not enjoyable! Normally associated with riding, or parties, but can be used for any situation.
2) when the soccer player can't kick the ball, he tried to kick, but for disability his feet can't touch the ball.
1) Eu não vou no aniversário dele (nessa festa/nesse passeio/nessa viagem), vai ser uma furada!
2) você viu a furada que ele deu na bola?! Era só ele chutar e fazer o gol!
Cattle grid. It could be literally translated as kill-donkey.
- Cuidado onde pisa. Tem um mata-burro por aqui.
- A égua do vizinho teve que ser sacrificada ontem.
- Nossa, mas por quê?
- Parece que ela ficou presa no mata-burro ontem a noite.
A woman or man that has had many lovers. The joke goes that they are like a "maçaneta" (doorknob), that they were hold by many hands. Normally used for women, as for men it is more common to call they galinha.
- Oh, aquela lá é maior maçaneta. Já ficou com a rua toda.