it means shut the *$#@ Up! or it can also mean your done talking or that your talking privileges have been revoked for the remainder of the day.
Some one is saying something stupid or they are about to say something they shouldn't so you cut them off and say "bup-bup"
作者 toxictrix 2009年10月15日
Can you define these popular missing words?
the dried tomato on the top of the ketchup bottle.
oh no, this ketchup bottle has bup-bup on the top of it, someone scrape it off!
作者 sydney brair smith 2008年2月18日