To superman a roach is the act of smoking a marijuana joint until it is basically too small to be smoked any more (more commonly known as a 'roach'), and then inhaling sharply and releasing grip on the roach, swallowing it.
"Do you guys know where 7-11 is?"
"He just swallowed (superman'd) the roach, mothafuckaa"
"Bro, you gotta superman a roach lol"
"Hell yeah man I totally forgot that was a thing... hold up I'm about to actually do that, sounds like a great idea"
'Roach' is a slang term for marijuana; specifically, when one 'pops a roach,' it's when that person has finished smoking a 'blunt' (marijuana rolled up inside of a piece of paper in smokable form), and all that's left is the very end of it which is too short to smoke w/o burning oneself and too small too hold in the hand anyways (w/o a special pair of tweezers used for just that). So, this 'roach' is popped into the mouth, chewed up, and swallowed.
A roach is prized b/c, after the blunt is smoked, it contains the highest amount of resin of any part of the blunt.
Now that we're almost done smoking this blunt, who's gonna get to pop the roach?
I've never got to pop a roach, b/c my friends always finished the blunt before I got it.