There are plenty of synonyms for the phrase "withed sound be in stitches". This phrase means to laugh uncontrollably or to burst out laughing. Some other synonyms for this phrase include chuckle, giggle, cackle, snicker, chortle, and guffaw. These words all describe different types of laughter and can be used depending on the situation. For example, "giggling" might be appropriate for a childish or playful situation while "cackling" might suggest a more sinister or dark situation. Regardless of which word you choose, they all convey a sense of overwhelming joy and amusement.