The act of intaking marijuana. Specifically from a "bong"
Guy 1: Here, pass the bong.
Guy 2: Thanks man. Gonna be toking up.
The specific act of lighting up a joint/bowl of marijuana (not tobacco).
You: You toke?
Me: Naw, but you can go ahead and get toking up.
The act of smoking marijuana to get high.
Me and Jim are going back to my place and toking up after class.
Verb
The act of smoking marijuana or tobacco, (although usually refers to marijuana) to get high.
Kit: hey, man, come over to Zoe's house tonight, we're gonna be toking up!
Donovan: awesome, I'll be there.
Taking a smoke; specifically describing the smoking of marijuana. It could describe smoking a blunt, or using a bowl, bubbler or bong.
Hey, I'm toking up in a sec, do you wanna go out back?
Toking up first thing in the morning gets you extra stoned.
"have you seen chris? he won't answer his phone..."
"lol he's probably toking up in his room and is too stoned to deal with u"