A close up top view of right hand during a rasgueado sequence. The 3rd finger ('a' or ring finger) is used to support the weakest finger, the pinky ('e' or little finger) during rasgueado strokes. The sample rasgueado shown here is ieam but the same applies to any rasgueado that uses the little finger.
It should be noted that this is not the only way to play a rasgueado. It's the way I do it. Another school of thought says you that should scrunch up the fingers into a tight fist and flick the pinky from the palm of the hand. I don't like that at all. It feel's far too tense. If anyone asks for tabs for this, I will personally come over to your school and let down your bicycle tyres.