This video of a physics experiment gone wrong will make every man cross his legs when he sees it. But that's nothing compared to the agony the schoolboy experienced.
It shows the moment a teacher attempts to show his class how to break a breeze block with the back of an axe while it's being balanced on the stomach of the teenage boy - only to strike him in the nether regions instead.
'Ouch!' really doesn't do it justice.
Why this is considered to be appropriate in a classroom is anyone's guess? Ditto what on earth the experiment is meant to be demonstrating.
Whatever the case, the hapless teacher is apparently no longer in employment judging by the tile of the YouTube clip: "How the physics teacher lost his job."
Oh, and how!
Story continues after video...
In the clip, the teacher appears to attempt to crack open a breeze block that is balancing on the chest of one of his students using an axe.
Standing with his legs either side of the pupil, the teacher swings the axe over his shoulder.
But as he brings the sharp-edged tool down towards the concrete block, he loses his footing and slips, striking to axe into the student's genitals.
The student flinches violently in pain before the 17 second video - which has been viewed more than 1.3 million times - abruptly cuts off.
We imagine the teen isn't thinking about fatherhood any time soon!