There is no precise definition of vulgar speech. You should use common sense and your own personal comfort level to determine whether something would be considered crude/vulgar or not. You need not maintain the same level of formality or refinement of speech with your husband as you would have when speaking with a rav or respected teacher.

For example, it is important for a couple to communicate about all aspects of their relationship, including intimacy. At one extreme there are crude, vulgar ways of speaking about intimacy, and on the other hand, there are formal, indirect ways of speaking about intimacy. But there is a middle ground of speaking explicitly (as opposed to merely hinting) without being vulgar. You can speak playfully and casually/informally with your husband without being crude. There is also a difference in your manner of speech when speaking in front of other people and the way you would speak privately in the bedroom.

We hope this helps answer your question. Please feel free to get back to us with any further questions.