It looks more like exhibitionism than a fetish. I suppose if guys get turned on by being whipped, pinched, pierced, bound, gagged, shocked, strangled ect., is it really that much different? If the pain stimulates endorphins, mission accomplished. It's just kind of risky messing around there, especially if blood is drawn. The resulting scar tissue can cause problems.
If you insert medical sounds in gently, it can be rather erotic... http://www.medicaltoys.com/Hegar3m.jpg
You generally start with the smaller sizes, and work your way up (use lots of lube!). They are really used for vaginal or urethral dilation (for men) if you have an obstruction or bladder problems...
The penis has a lot of sensitive flesh - and vital nerves. This idiot clearly does not intend to keep his vital organ "healthy" for long. Damaged blood vessels, internal flesh tear wounds or even worse - if the pen or object is at the very least infested, could lead to him contracting a urinary tract infection - which is unpleasant to say the least.