The 2 bar exit is a stop method originally intended for longer timeframes (4 hours). It was designed to make calculation of stopping points easy and to lock in profit as soon as possible without smothering the trade and ending up with a fraction of the pips available. The beauty of these exit methods (this one, the crossover, etc.) is that they eliminate subjectivity (an enemy to most traders) and still provide for a good exit point towards the end of a move.
Once I've established an entry I'll put a stop in place on the 5 minute about 6 pips (GBPJPY spread) beyond the lowest/highest point of the previous two candles to the candle that is now forming on the 5 minute. (** Look at the current candle forming...count the 2 completed candles to the left of that one. Take the lowest/highest point between those two candles, add in an additional 6 pips cushion and that is where you set your stop). At this point if I need to go to the bathroom:beer::beer: or get a drink I have at least 5 minutes to do so. Every 5 - 10 minutes I observe price action and move the stop up accordingly.
See the attached chart for a couple of examples. Disregard the entries as I just chose those arbitrarily as a starting point, not due to valid entry criteria discussed on this thread.
Cheers