Not to rain on your parade but I would think that a Dog is not meant to handle a human erection. Despite what you have read the size of a K9 erection is not as big as a humans. No I am not an expert in Dog dicks but I have or had a male Labrador and he was not that big. It kind of had a mind of its own. and he would spend hours licking it.

I would think, unless the dog was a huge breed. Great Dane bull mastiff Irish wolf hound. You would end up hurting it and you would probably get bit, Rightly so.

Don't think it is a good Idea. Now if you are looking for the humiliation factor then maybe. I heard that there is a website called the Darwin report and it had a man who tried to have sex with a poodle. Turned out the he was to big and the poodle clamped down and he could not get it off of him. He had to go to the ER to have the Poodle removed. Poodle died of shock. Not a good thing but if humiliation is what your after then I so pose that would be pretty humiliating.