2 definition by Radium:)

Bagging involves spraying a can that contains aerosol such as hairspray or deodorant into a bag and putting the bag over one's head and inhaling the fumes in an effort to get high.

A fetch is a creature from irish folklore that is pretty much a more dead and rotted looking doppelganger of the person who is afflicted by the fetch. It is a harbinger of death and whoever sees their fetch will likely die in the coming days, weeks, or months.