What is the ruling on mentioning a woman's nakedness or "تشبيب" (eulogizing her beauty to incite desire) in Islam?

A man is permitted to use tashbeeb (amatory poetry) with his wife, provided he does not mention her private parts that must be concealed, and that his tashbeeb does not contain obscenity. It is also permissible to use tashbeeb with an unspecified woman, while avoiding forbidden words. As for tashbeeb with a specific woman who is neither one's wife nor bondwoman, it is forbidden and invalidates one's testimony. However, tashbeeb with one's wife or bondwoman is not forbidden, but it is stipulated not to do so excessively. One's testimony is invalidated if he engages in tashbeeb with them in a manner that entails a loss of muru'ah (chivalry/dignity), such as describing inner private parts.