Medically, it is wheb someone puts there finger up your ass about two inches and gently rubs your prostate through the lining of you rectum. This causes you to become hard and ejaculate. Procedure is used when necessary to test the prostate and/or get a semen sample.

Obviously the erection and ejaculation have hobby aspects. So useing the same technique, some little cutie massages your pole while gently sticking a finger up your ass and proceeding as described above. Done correctly she can get you to pop in no time at all.