The state of mind a male enters when he subconsciously has a
sexual fantasy, usually in the middle of class, church, a movie, at dinner, or any other
inappropriate time.
It isn't until about three minutes into this
mental state that smiles and boners occurs within the male and he realizes that he has been having sexual fantasies for an extended duration of time.
The temporary phase usually lasts until the boner becomes obvious, someone notices the male's lack of attention, or some other stimulus draws the male out of his state of arousal.