Is Necrophilia an insane experience or of Optional Choice

In book Civilization Before Greece and Rome, by H.W.F. Saggs; wrote; Herodotus heard that the embalmers has a name for their treatment of the dead, and reports that the bodies of beautiful womenwere not handed to them until three or four days after death; one embalamer, he says had actually been caught in the act of necrophilia.  But what is the relevant connection between  a Sexual Arousal and Orgasm, well we have learned that there are three stages to this. Kaplan's model differs from most other sexual response models as it includes desire - most models tend to avoid including non-genital changes. It is also important to note that not all sexual activity is preceded by desire; as usually thought  1) Desire 2) Excitement  3) Orgasm.The excitement or sexual arousal phase kicks off the male sexual interest.  The most obvious physical sign of sexual arousal in men is erection of the penis. The increased blood flow into the penis causes it to stiffen. As the spongy tissue inside becomes filled with blood, pressure is put on the veins inside the penis which prevents blood from flowing out which helps to keep the penis hard. World History exposes one to all of these  sexual information, but the so-called spirit-God Christian bible..and why.