Pushing Rope is when you are banging a girl all night, either repeatedly or multiple times, and finally your rod craps out on you. Instead of thrusting with your best foot (member) forward, you are instead pushing a limp noodle, hence the term, you are pushing rope.
This can also be referred to the term "whiskey dick", full sail, no wind (as you have full intention, but no control of whats going on)
Suzy and I were so into it last night, we were banging till I was pushing rope!
Buddy, I was so wasted last night, I was pushing rope.
It is said of the situation where a person has the bad luck to make contact with his testicles against an undefined surface or object, intentioned or not.
Given the nature of the word, it is more appropriate to design cases where the interaction is made with a moving object, for example, a ball.
Although it is extremely painful for the victim, it tends to be considerably funny to people who witness it.
Today in the baseball game the pitcher took a nutshot; the baseball hit him in the nuts.
Man, I just watched the funniest nutshot video ever.