The smart mammals demonstrate an instinct to sex and that instinct is. Screw the warm stuff. Well not quit. But the smart mammals often engage in non-reproductive sexual contact. It's done with same-sex couples. It's done with others too young to reproduce. Sex for pleasure's sake is instinctive and common and no emotional trauma with the mammals too young to consent has been observed that I know of.
"Bad Touch" is a social taboo, not a natural truth.