Bissing is a word that refers to the action of smoking a spliff. It can also be used in the context to say you're high, such as "I'm bissed".
Bissing can also be an action someone does, generally in a negative connotation, as well as being able to describe the state of being pissed off from such an action.
This word can also be used to describe the weather, such as to say for heavy rain "It's bissing it down"
Piers pushed Ollie down the stairs, and in the process had a bissing, while Ollie was bissed off