I suppose some guys are a bit different but any tactical self-defense class will teach women to go for a guy’s balls in a time of doubt, so I suspect all of us are capable of keeling over in agony if given the right strike. When trying to explain this to women, a direct hit on the nuts, even like a really hard flick can be just as devastating as a kick.
However, there is a happy place that feels great and you don’t have to be super gentle either. Pull an entire ball inside your mouth. That feels great, but that is because you didn’t do a direct hit on his nuts.
Think of it like this: an egg with a shell. If you drop it or hit it, it will crack or at least splinter. That is the pain for us. But if you pull that egg inside your mouth, lick it up and down, suck it, it fucking feels great. That’s the best I can explain it.