I've never seen an issue with it.
So, I let my dog fuck me regularly. In case anyone thinks I'm forcing him into anything, I'd like you to focus on two words in that first sentence; *let him*. I don't force him to do anything, and the hardest part of training was getting him to not hump my leg when I've got company over, and he was trying to do that before I ever thought of touching his cock. Much like a support dog who knows how to predict a seizure, he has a signal to tell me he wants sex and how he wants it(who trained who, ha-ha). We fuck almost every day, sometimes several times a day if I'm home all day with no company. He prefers my asshole most times, but he'll never turn down my pussy, or a blowjob or rimjob(though, I will say, if his preferences are normal in the canine world, I've seen a lot of videos of women who don't know how to do a dog rimjob right).
There is nothing wrong with it
You got a vivid imagination and need to get out more amongst the living.
Lots of old women get Yorkies because no one suspects that they have 5 inch rockets
My wife used to let our dog fuck her. It was always hot.