To shut ones mouth as demanded by another.Used especially well when someone is talking out of their ass. For added effect
it goes well in almost a sing-song type usage.
chup-chup-chup
your mouth, chupchupchup your mouth!
Hey greg you don't know anything so chup boy!
For the sing-song usage just
drag out the U and
bring it up an
octave in the middle, then back down at the end: chuuuuuUUUUuuuuuuup.