when someone is so close to orgasm that he or she cannot stop having sex/masturbating, regardless of the circumstances
"I heard my roommate coming up the stairs, but I was already at the point of no return so he opened the door just in time to see me blow my load all over my desk."
The moment just before you have an orgasm and ejaculate. You cant stop the semen from coming out, it just comes. It is and unstoppable force of nature. There is no holding it back.
Jonny didnt want to ejaculate, but he hit the point of no return and it was all over. His semen filled his lovers mouth....she was so angry she spit it at him.