Experiencing pain/humiliation is ESSENTIAL for sexual arousal.
A 19th century psychiatrist, Richard von Kraft Ebbing spoke of "basic natural tendencies to sadism in men and masochism in women."
The philosopher Jean Jacques Rousseau in 1782 wrote "Confessions" in which he said he derived sexual pleasure from the beatings he received as a child.
In the KAMA SUTRA (India around the 2nd century) it says "For successful intercourse a show of cruelty is essential."
Why the interest in Sado Masochism? Well it could be an underlying driver for GUANO and the GUANOHEADS MO.
They are quite cruel and seem to delight in inflicting pain figuratively or literally. They are unkind unjust unfair unhinged. Now the sex drive makes some folks wackadoodle diddlewaddles. PERVERTED sex drive obviously enhances that.