I tried a lot to find it here but I can't, I don't know if I just kept missing it or if it has been taken down by the author or mods.
So this is how it went a woman invited her neighbour who is suburban mom to take part in busting her husband or boyfriend. They place his balls in some device with screws tightening it. The mom is surprised to know that there are guys who can enjoy this , when the mom talks about crushing her boyfriend's balls his cock twitches up and stuff. They both notice this and keep talking dirty to him about castration and similar stuff. Finally he spurts and the girl asks the mom if she would like to come to their next session