The phrase "hotting it up" means to increase the intensity or excitement of something. There are several synonyms for this expression including ramping up, cranking up, heating up, intensifying, accelerating and revving up. These phrases are often used when describing a situation or event that is becoming more intense or exciting. For example, a sports game might be described as "heating up" when one team starts to score more points, or a party might be said to be "ramping up" as more people arrive and the music gets louder. In general, using these synonyms can help to add variety and excitement to your language.