Regardless if OPs boyfriend liked it or not, there ARE guys out there that do. I actually got a message from some perv on here a while ago asking if I would kick his balls if he payed me $50.
54, I'm grossed out on your behalf, but sadly, I'm not surprised. I made my comment in jest, but I have seen certain...websites devoted to the genre of cock and ball torture, enough that I'm sure there's an audience interested in re-enacting the contents IRL. -___-
Which means, 81, that there is nut-shot porn, which means by extension that there are guys (and gals, but we all know who watches more porn) who are into it!
There's a difference between hitting a tendon or muscle or whatever and your leg moving, and you moving it yourself. They're different types of reflexes.