spunkknock
to get hit in the gonads, the testes, the balls, boyos, whatever you want to call them. Generally used to describe this occurance when it happens by accident or bad luck as opposed to malevolent intent
"Man, did you see that spunkknock?"
"Yea, he'll be feelin' that one for weeks"
"Yea, he'll be feelin' that one for weeks"