A guy who is often observed to be thinking with his dick in any given situation or a guy who switches into a lusty, lewd, crude and foolish person A man in that mode can also be quite rude. They tend to zone onto the female person or persons of interest, to the exclusion of all others.
Dude, you brother could be taking to mom while he's checking out the talent on the street as if he's eternally in some penal mode! Whenever Valencia walks by we all become invisible when he switches into that penal mode shit, acting like some crass fool! Tell him to snap out of it man and give us and her some respect!