The panic that ensues in a situation when one realizes that he has an extremely limited amount of time to hide or minimize porn before being caught. Often occures late at night when one thinks he is alone to enjoy porn but is alerted to the sound of someone approaching. In the days before the wide spread use of PC's, this panic was often defined by the sound of magazines being shuffled into a drawer or thrown under a bed. If one's reaction time is too slow, this can lead to being caught red handed.
Johnny had a porn-panic today when he was trying to minimize a porn screen on his PC as his mom came up the stairs to check on him.
Having had a parent/friend/spouse come dangerously close to finding their stash of sweaty knuckle material (be it tangible and therefore most likely hidden under a mattress, or in a file marked 'Holiday Photos' in the deepest, darkest bowels of their computer) the act of feverishly deleting/burning/disposing of this material occurs in what is collectively known as a 'Porn Panic'.
"Hey Brian, I heard you had naked pictures of Michelle from our old school class, can I see them?"
"Sorry mate, I did, but the missus was poking around on my laptop and came dangerously close to finding them so I deleted everything in a Porn Panic"