attention: NEVER TRY IT AT OTHER COUNTRIES :p
Body Language
Obscene, to be used with extreme moderation!
Screw You
This is very similar to the American OK, but it's VERY obscene! It means "screw you" like the gesture in the picture above. There are countless jokes in Brazil about unknowning Americans making the OK sign to signify approval or pleasure. Please, train yourself to use the "thumbs up" sign instead. I remember years ago in Rio, we were at the movies and they were showing a newsreel before the film. When Richard Nixon appeared making the OK sign, some clown in the audience yelled "that's what he's doing to the American people." Everyone in the theater broke out in laughter, of course, and we were laughing for quite a while!
Banana
This is called "dar uma banana" or give a banana and it means "screw you!", so use your discretion...It's probably better to avoid it, so you don't get into a fight, but I always taught it to my students, as part of their general education in Brazilian culture.
The Finger or Up Yours
Same as in the U.S. (my comment: we flashed this whenever we are angry or cranky!)
Saco Cheio
Hold your cupped hands in front of your lower body and shake them. This gesture means "my balls are full" (the anatomical reference is clear...) and has become so commonplace that, depending on the circumstances, it's not obscene at all (and it's used by women also). It's best to avoid it, though.
Screw You or I Screwed Up
Make a fist with one hand and slap the top of it with the other once or twice. It means screw you and "I got screwed" or "I screwed up" (like in a test or something, often accompanied by the expression "entrei pelo cano"). It's very commonplace among friends in informal contexts, but you'd better avoid this one, too.
link: http://www.maria-brazil.org/brazilian_body_language_obscene.htm
sooo....
SCREW YOU!!
hahahahaha
PLEASE SUPPORT!! 
