The phrase "go OTT" is commonly used to describe someone who goes over the top or excessively in a certain situation. There are a number of synonyms for this phrase that can be used to convey a similar meaning, such as "go all out", "go overboard", "go too far", "exaggerate", "overdo it" and "push the envelope". These phrases can be used in a variety of contexts, from describing a friend who is partying too hard, to a colleague who is taking a project too seriously. Regardless of the situation, these synonyms effectively communicate the idea of going beyond what is necessary or appropriate, and can be a useful addition to anyone's vocabulary.