The act of smoking marijuana with close friends. Most preferably out of a Blunt.
Homie 1: What's up fool?
Homie 2: Not much, you fin' to yoast right now?
Homie 1: Nigga I'm always down to yoast a blunt
It's when you cook the egg inside the bread. So you get egg-toast, or yoast. Like in the movie V for Vendetta.
V: "Do you fancy some yoast on this most vivacious of Vonember noons?"
Evey: "Why yes, I most certainly would."