The phrase "gat last drop" is a colloquial term used to express consuming every last bit of a beverage or food item. Some common synonyms for this phrase include "drain," "finishing off," "emptying," "clearing out," and "polishing off." These terms carry the same connotation of consuming all of something until there is nothing left. Other related phrases that could be used as synonyms include "licking the plate clean," "drinking to the bottom," and "scraping the bowl." Using these synonyms is a great way to add variety to your language and enhance your expression of the concept of consuming everything.