I didn't know about Buffalax (the YouTube user) or Buffalaxing (the verb) but here's the first example of the art that I've seen. A definition?

"A song in a non-English language that has been given subtitles based on what the foreign words sound like ... is said to have been Buffalaxed. This word comes from a genius on YouTube whose username is Buffalax."

I'm now off to watch some of Buffalax's oeuvre.