When it comes to discussing intimacy, the phrase "between the sheets" is a commonly used euphemism. However, there are plenty of other synonyms out there that can be used in its place. Some of these include "under the covers," "in bed," "wrapped up," and "cosying up." Additionally, there are more explicit synonyms such as "making love," "getting intimate," "romping," or "having sex." The use of any of these phrases largely depends on the context and the relationship between the individuals involved. Regardless of the exact wording used, it's important to always respect one another's boundaries and communicate openly and honestly.