Try to watch some Brazilian movies! You can see slangs there all the time.

In Rio usually we say a lot of bad words, like "porra". Não se assuste haha Here a video about it https://www.youtube.com/watch?v=14Cnqb04b20

sites; Cariocas - http://canalviva.globo.com/programas/mais-da-tv/materias/dicionario-de-girias-cariocas.html http://falarcarioca3004.blogspot.com.br/2012/11/girias.html paulistano - http://www.cidadedesaopaulo.com/paulistanes/ http://exame.abril.com.br/brasil/noticias/30-girias-de-sao-paulo-que-e-preciso-aprender-antes-da-copa creio que já está bom. já pode "trocar uma idéia " no Rio e em "Sampa." (São Paulo).

I think browsing Twitter or other social networks and reading what people say would be enough for you to get a basic grip on slang, maybe listening to rap songs from these places as they tend to use a lot of these words. However, if you really want to learn this kind of stuff you must go live there or start language exchange with someone that's a native from these places.