That's called a penile fracture and yes, its a thing. I got chills down my spine just writing these words.
Here's a gem of information on that topic, stolen straight from wikipedia:
Taqaandan, which comes from a Kurdish word meaning "to click", involves bending the top part of the erect penis while holding the lower part of the shaft in place, until a click is heard and felt. Taqaandan is said to be painless and has been compared to cracking one's knuckles, but the practice of taqaandan has led to an increase in the prevalence of penile fractures in western Iran.
Now if you can get a fracture by clicking your shaft imagine what someone's entire bodyweight slamming down on it could do.
So dont fuck around with rough cowgirls unless you like to live dangerously. Abstinence is the safest option.
As for me, well i guess my middle name is "danger". ;-)