In the video below Braulio Estima, ADCC 2009 88 kg and Absolute Champion demonstrates how he sets up the Inverted Triangle that he used in the competition.
The set up that he demonstrates in the video is from the side mount but you could easily get into position from a number of other positions including the Butterfly Guard, Half Guard ...
This is kind of an unorthodox attack for BJJ. You see this and the North South Triangle among others more in Judo competition.
