ejaculatory inevitability
The point during sexual intercourse where the male realizes he is about to cum (ejaculate) no matter what he does to stop it. Usually at this point semen has already entered the base of the shaft of the penis, so the male cannot stop the ejaculation process no matter how hard he tries.
Grunting and groaning and kegeling didn't help he had cum up his shaft and he was at his point of ejaculatory inevitability.