LAST RESORT

If you have lost control of the orgasm and are certain that the technique will fail, you can use strength to flex your PC muscle against your finger, which creates an impenetrable barrier between the exit and the source of the ejaculate. Notice the involuntary pumps and focus on flexing your PC muscle until all waves have stopped. You will likely lose your erection but may manage to hold it back regardless. The sperm will not be redirected to the bladder.