There are many similes in this chapter. Their purpose is to describe the beauty of the woman. The woman is described as the epitome of beauty in ancient Israel. In 7:1-9 the man speaks to the woman. In some versions this is 7:2, the second verse of chapter seven.
"The curves of your thighs are beautiful like the beautiful curves of jewel that a skilled craftsman has made". The word "thighs" refers to the hips of a woman and the part of her legs that is above her knee.