Hot Up Meaning

(idiomatic) To become more heated.

Example: To heat up:
  Wait for the water to hot up before adding the salt.
  The choice of a new leader hots up.
To make or become more sexually appealing, enticing or exciting.
1997, Theatre Record, volume 17, issues 18-26, page 1644:
  We move to Twankey's launderette, where the Aladdin/Bathroomdoor romance hots up.
2001, Sayan Chatterjee, It all adds up to love, page 40:
  Arvind and Shiela's romance hotted up.