Cornering, also known as corner roasting(also as corner tapping) or half greening, is a technique used by smokers of cannabis to help limit the destruction of tetrahydrocannabinol by the heat of the flame used to ignite the material being smoked. Proper use of cornering can extend the life of the material being smoked and is a necessity to avoid the complete destruction of kief. Cannabis Sativa Look up marijuana in Wiktionary, the free dictionary. ... Tetrahydrocannabinol, also known as THC, Δ9-THC, Δ9-tetrahydrocannabinol (delta-9-tetrahydrocannabinol), Δ¹-tetrahydrocannabinol (using an older numbering scheme), or dronabinol, is the main psychoactive substance found in the Cannabis plant. ... Kief on Parchment Paper. ...

The most important aspect of cornering is to never let the flame touch what the user is smoking because tetrahydrocannabinol is destroyed by low temperatures compared to the heat of a flame. To properly corner the user elevates the flame above the material being smoked and draws slowly. When done properly the heated air alone will cause the material to start to combust and consequently the flame never touches.

As a side effect smaller portions of the material are incinerated for each smoker. Because cannabis is usually smoked communally this allows a larger number of smokers to get a green hit or greens (since the bowl still has green rather than burnt brown material) which is highly prized. This article or section does not cite its references or sources. ... Bowl used for smoking marijuana Bowl is used by smokers of cannabis to indicate one of two different things: The bowl-shaped receptacle in which marijuana is placed prior to smoking which forms part of a marijuana pipe or bong. ...

The opposite of Cornering is Torching, also known as Roasting, "Scorching the Earth" or "Mowing the Lawn", which is sometimes considered a form of Bogarting.