I don't have a dog, just wanted to make that clear from the outset here.
My sister-in-law and her hubby do though. They have a 'baby' St. Bernard, Baxter.
He goes about 215#'s these days. He likes to ride in the Mustang John has had since his college days. It's a convertible and Baxter takes up the whole back seat.
One day, while out for a ride, John notices that Baxter has to do his thing. So he stops and puts Baxter on the leash. As soon as he opens the door, Baxter takes off like a bolt of lightning. Said leash is wrapped around John's left hand and fingers, which promptly give way to the fast exiting dog's pull.
A couple of surgeries later, John is on the mend.
At least he was still able to hold his beer.