Hmm, I was thinking this one over as I was crocheting a blanket tonight.
It would take one heck of a gullet to suck Coke through that PVC pipe! You'd have raspberry face before you got your first sip, go ahead try it at home!
A much better bulk Coke dispenser would've been made by taking some thin tubing, like air lines for an aquarium air pump, taping that to the edge of the trash bin, so one end of the tubing is just touching the bottom of the barrel on the inside, and the other end comfortably reaches your maw.
Now elevate the trash can so the end of the tube that's in your maw is lower than the bottom of the barrel. A bar stool would do nicely. Prime the dispenser by sucking on the straw and then let the gravity do the rest of the work of delivering the sugary sludge into your crop.
If you need to stop the flow, simply fold the end in half to crimp the tube and if you are going out for a while, duct tape the crimp together, so it doesn't straighten. Of course, you can use a flow control valve from same aquarium equipment, but that may not be MacGyver enough.
Of course if you don't have a fish tank, you can take a package of soda straws and make one long one by sticking the ends of straws into each other and putting tape on top so the ends don't disconnect by accident.
Yes, go ahead and laugh. I can take it. :-)