Option selects change the way that any fighting game is played. The more inputs that you can cram together, the more situations a given option select will apply to. Naturally, this makes top players incorporate the option selects that offer them the most bang for their inputs.
In the video below, Paul Morpheus shows off a version for Fei Long that affords him advantages in a downright alarming amount of scenarios. The technique will tech throws as well as toss an uppercut in the event of a frame trap, which effectively covers the glaring weakness associated with crouch-teching. Fei Long will even block if the given situation warrants a block.
As you might expect, the timing involved is pretty tight and can change slightly depending on the situation at hand. Paul says that doing this multiple times in a row when being pressured is incredibly dangerous because it’s more complex than a simple crouch tech and because the aggressor has the advantage of staggering the timing of their pressure to mess it up.
This option select will work with any character who has a reversal with a standard dragon punch input, but since Fei Long uses a backwards motion in order to execute his reversal, he has the easiest time remaining safe during the technique. As with anything like this, there are weaknesses involved and Paul dedicates a good deal of the video to showing exactly what kinds of things players can expect to beat it out.
Source: Paul Morpheus