(Verb) To terminate something in an abrubt or unexpected fashion. Derived from the sudden ending of Sergio's (BE) performance ("Sister") at the Eurovision songfestival in 2002.
After Jack was diagnosed with several STD's, he sistered his relationship with Svetlana.
"Art. 3: Watching midgetporn during working hours will sister this contract of employment and nullify all duties of the employer."
The problem with urinating from the Eifeltower is that you can't sister if the security guard catches you.