Used to signal idiocy in others by fabricating a sympathetic audience or camera, accompanied by looking in the other direction and gesturing towards the person at fault. Not specific to males.
If someone says or does something that deviates from the normal activities or expectations of the current social company, "this guy" could be used.
An employer that asks a slacker to do his job may look at other coworkers, or just away from the boss, and motion towards the employer with exasperation and say "this guy."
Taken from movies that have characters who "time out" to talk to the camera.