Here the idiom "uncover the nakedness" means "disgrace." Alternate translation: "Do not disgrace your father's brother" or "Do not shame shame your father's brother" (See: [[rc://en/ta/man/jit/figs-idiom]])
You may have to make explicit the purpose of the approach. Alternate translation: "do not go to his wife in order to have sexual intercourse with her" (See: [[rc://en/ta/man/jit/figs-explicit]])