This is normally only performed under extreme intoxication (tri or even quad fade) and is often associated with listening to heavy-metal music, although it may be performed at any time, you'll just look totally ridiculous while doing it sober.
2) He's doin it!
"Hey what's up? - Doinnnnnn' itttttt"
"We're doin' it. Are you?"
"Let's doin' it"
"Where are you doin' it?"
"Delta doin' it"
"Mark's definitely doin' it"
"How much more doin' it will it take to be doin' it?"
"I can't doin' it anymore. Wait... nope, still doin' it"
"DELTA!.... doin' it"
"My dad told me to stop doin' it, so I told him to f**k off"
"How long til' the kegs get here? - T-minus doin' it"