Once one is agitated by lusty desires upon seeing a woman, those desires increase more and more, but when semen is discharged in the act of sex, the lusty desires diminish. The same principle acted upon Lord Siva. He was allured by the beautiful woman Mohini-murti, but when his semen had been fully discharged, he came to his senses and realized how he had been victimized as soon as he saw the woman in the forest. If one is trained to protect his semen by observing celibacy, naturally he is not attracted by the beauty of a woman. If one can remain a brahmacari, he saves himself so much trouble in material existence. Material existence means enjoying the pleasure of sexual intercourse (yan maithunadi-grhamedhi-sukham [SB 7.9.45]). If one is educated about sex life and is trained to protect his semen, he is saved from the danger of material existence.