Do a moonie
Definition 1 of 1
Pro Tip 1/3Cultural Sensitivity
Considered rude and inappropriate in most situations; use only in very casual settings with like-minded friends. 
He thought it was funny to do a moonie, but not everyone appreciated the humor.
Pro Tip 2/3Legal Implications
It may be illegal in some places, potentially leading to arrest for indecent exposure. 
She didn't realize that attempting to do a moonie during the parade could lead to legal trouble.
Pro Tip 3/3Not Workplace Appropriate
Absolutely avoid this phrase and action in professional or educational environments. 
Even at the informal office party, it's unacceptable to do a moonie.