You guys have to be super careful when adding it until the engine dies. I would not recommend that AT ALL. You run the risk of Hydrolock which is NOT worth it.
The way I did mine; I removed the intake tubes, so I had direct visual access to the butterfly valves. I removed the brake booster vacuum line, and held the seafoam up against the line so that you can see the vacuum pulling out the liquid through the Venturi effect.
I let it lightly draw seafoam at idle, just enough to make the engine stumble. Then, I manually open up the throttle to increase RPM's to roughly 2000, and add lots of seafoam. At this point, the engine won't die because the seafoam is burning too quick to kill it. I would add as much seafoam as I could, and if the engine almost died, I revved it more. The truck blew smoke like a train the whole time. I did this with the entire can, and afterwards, my idle was significantly smoother, and the throttle response was fantastic. IMO a much safer way to clean out the engine.