If you're in the middle of a sesh/sharing a smoke and you feel it is your turn for a hit. You simply say clinch it. And the smoker will take one last hoot and pass.
The Clinch is the embodiment of STI's. The Clinch can spread infection through proximity, saliva, blood, urine, and other means not yet identified by modern science. Some evidence suggests persons can contract a variety of infections from the clinch via text messages, msn, or even from excessive facebook creeping. Currently the only known prevention from contracting Clinch based virus' is abstaining from excessive contact with the Clinch.