I love it! I've sucked a dog before I'd gotten to suck a human (at least, a full fledged blowjob). I enjoying giving a blowjob and swallowing, don't get me wrong, but it's not the same.
I'll never forget my first. A white shepherd mix. The taste of his cum was addictive. I didn't get too many opportunities, but it was wonderful. I loved that dog
Mouth fucking sounds crazy hot, but I'm too nervous to risk any kind of injury for the dog. I'd love getting one of those penetrables made to use while giving a blowjob, though.