some of the gestures used by cariocas are popular across international borders, like the 'come here' sign, or the 'call me' sign - the people of rio are wont to use them at any opportunity, often opting for the physical gesture over a linguistic explanation - when the index finger and thumb are brought together in a circle it represents the universal sign for 'ok', however when upside down in brazil it has an uncouth meaning and should be avoided at all costs. 

a brazilian may appear to pinch his earlobe between thumb and forefinger to express their upmost appreciation and satisfaction that  something is exceptional.  anything from a superb job well done, to a scrumptious and delectably prepared dish, or a top-notch quality item or occurance - the pinching of the ear represents complete satisfcation. 

in order to show that one does not know the answer to a question, there is a swipe of the fingertips underneath the chin that end with an upward palm in front of the face, away from the body, with a shrug of the shoulders.