Praise be to Allah.
It is permissible for both husband and wife to say whatever they want to provoke desire during intercourse, and that does not have to be something that was narrated in the Sunnah, but it is not permissible to say anything that is forbidding in Islam, such as lies or slanderous words. But with regard to mentioning the genitals by their colloquial names or other things that provoke desire in word or deed, the basic principle is that it is permissible.
Some of the scholars are of the view that this is makrooh, and they regarded it as contrary to proper etiquette. But the correct view is that it is permissible. Even if we accept that it is makrooh, then that ruling may be lifted when there is the least need for it, and the need here is obvious.
If it is permissible for the husband to touch his wife’s private part, look at it and enjoy it, then it is more appropriate that he is permitted to call it by a name that will provoke his wife; and the converse is also permitted.
See also the answer to question no. 13621
And Allaah knows best.