The phrase "lather up" is commonly used to describe applying soap or shampoo to create a rich foam. However, there are several synonyms that one can use to add variety to their language. "Suds up" or "froth up" can be used instead of "lather up." Other options are "bubble up," "foam up," or "creamy up." These alternatives are perfect for adding a touch of creativity and expressiveness to your writing or speech. So next time, instead of using the same old phrase, try one of these synonyms and see how it adds a spark to your communication.