Question:
Why did Adam and Eve put the leaves around their waists?

Answer:
One thing is clear that God did not tell the man and the woman to put the leaves around their waists. They made that decision themselves after they had sinned. “And the eyes of them both were opened, and they knew that they were naked; and they sewed fig leaves together, and made themselves aprons” (Genesis 3:7).

Satan had promised: “Ye shall be as gods, knowing good and evil,” but after they had sinned they saw no beams of divine light. Eve probably thought that they would see wonderful things that they knew nothing about before, but all they got after they sinned was a consciousness that they were naked! They received a knowledge of being evil themselves by their disobedience, and they were ashamed of the miserable state that they had gotten themselves into before God. And so, before God said a word to them, they became judge of their own state, and they were ashamed of it, and covered the part of the body that produces waste, and provides reproduction of mankind. I don’t know if we are told in Scripture, and if we are not told, we do not need to know. But it is evident that they covered their waists simply because they were ashamed to have them not covered.