She's at her best when 'the heat is on'. [=when she feels a lot of pressure; when she needs to finish something quickly]
She said things in 'the heat of the moment' [=when she was angry for a short period of time] that she later regretted.
The company has 'turned up the heat on' [=has put extra pressure on] its employees to finish the job quickly.
(..) Okay, thanks for the help. I can take it from here. Hey, you over grown weasel . Wait till we get down there. The whole South thing is way out. The heat, the crowd. This great. You and me, two guys knocking about in the wild. No, you just want a bodyguard so you don't become somebody's side dish. (..)2002 Ice Age