If your friend asks you to look after their dog for a couple days, please make sure you leave your stash lying around, and the dog unsupervised.
Then, when you take the dog into the vet for "acting scared/shaking slightly" and "having trouble walking, like he's drunk or something" (which are often pot dog symptoms) you should cover up the fact that you have some awesome cali hydroponic weed in your house by explaining that "well, maybe he had a seizure, but I didn't see him twitching or anything" (dog had been previously worked up ~1 month ago for a "possible seizure"-- all labs normal, no neuro consulted, o's previous pet died from sz disorder complications, so o's very paranoid about anything related to seizures).
When you tell the vet these things, he will believe that the dog did indeed have a seizure, and give said small dog two huge doses of valium, to see if he can get it to stop tremoring. When this does nothing, he will then give it a huge dose of pentobarb, "to effect." The "effect" of the pentobarb will be that the dog is now comatose and unresponsive. The vet will now explain to you, the totally freaked-out pet-sitter, that this dog will be comatose for a minimum of several hours, possibly up to "forever" and that you should take the dog to the 24/7 veterinary ER where I work for supportive care. En route, said dog will go into shock and show up at my hospital on death's doorstep with a BP of ~60 and a temp of 93 and some change. This will all be REALLY HARD TO EXPLAIN TO THE ACTUAL OWNER OF THE DOG, when she arrives at the emergency vet hospital in hysterics, to find her small dog in a baby incubator with an ECG, a constant rectal temp probe, and an IV line.
It will however, give me something to do for the duration of my shift: namely, sit next to aforementioned dog and evaluate mentation on the coma scale Q2 hours, and trying to keep it from freaking out too badly as it slowly, slowly revives from the depths of its lovely THC/valium/pento induced disaster. oh, and also talk to the real owners Q 30 minutes as she keeps calling back to see if her baby has "woken up" yet. (No, ma'am, sorry, we really don't anticipate any changes for at least a few HOURS, but yes, feel free to call for updates at any time!)
Little dog was actually sternal and somewhat alert by the end of my shift, although definitely still in La-la land... As far as I know he went home the next day with no major, long-lasting effects! Sturdy little dude!