It was derived from the the Wii game Mario Party 8, because they have a game called shaking the can where you shake the controller as hard as you can and it looks like you are masturbating.
Trevor asked his friends to leave the room so that he could begin Shakin the can to some gay porn
From the game "Shake it up" on Mario Party 8 for the Wii, in which a player must shake his/her can for 5 seconds and whoever has the highest stream wins. Naturally, this became a great innuendo for jerking off.
The act of engaging in male masturbation. The pringle can represents the subjects penis, while the shaking represents the motions made by the males hand to simulate a vagina and/or anus. During the shaking process, it is expected for the male to have some type of masturbation "material" such as a pornographic DVD or perhaps a pornographic magazine. The shaking process can last anywhere from a minute to over an hour, all depending on the situation.
Babe, I was shaking the pringle can all last night, but here's the sweet part, I didn't even use any masturbation material, I used thoughts brought from my spank bank.