There are several synonyms for the phrase "hots it up". Some common alternatives include heats up, intensifies, accelerates, quickens, and amps up. These phrases are often used interchangeably to describe situations where things get more exciting or intense. For example, a sports commentator might say that the game is really heating up in the second half, or a musician might amp up the crowd with an energetic performance. Other phrases that convey a similar sentiment include "turn up the heat", "raise the stakes", and "spice things up". No matter which phrase is used, the intention is to convey a sense of increased energy and excitement.