Steamin' Fun!

Christopher's new word is "steamin'" - as in "It is steamin' hot outside!" However, he seems to have given up all other modifiers in favor of the "steamin" awesomeness of the word steamin. Like -

• It's steamin' cold outside.
  
• I'm steamin' good at Star Wars (Lego version on the DS - his favorite game)
  
• I'm steamin' fast
  

and many others which are too numerous to name. I can't figure out where it comes from...