As I type this, there’s 65 pounds of ugly-ass junkyard-looking dog assiduously licking his penis, in case you’re wondering why the question comes to mind.
Dogs lick their junk. Every damned dog in the world, in my experience. (For some reason, I’ve only had male dogs - I don’t know if this applies to females.) Captain is neutered, probably when he was a puppy. God knows nobody in their right mind would breed more dogs that look like him. But when he licks his legs or whatever (and I think he has some sort of skin issue) you can pull him off himself and he stops. When he’s licking his penis or penis-area, it’s really hard to pull him off. Also, right now he’s snorting at it.
So does a neutered dog receive sexual pleasure from licking himself? I note that that area also seems sensitive in the “hair rubbed off of leg-meet-belly friction points” way, so that could be a cause. But seriously, he seems surprisingly into it, if you know what I mean.
Female dogs do lick themselves there, but it seems to be more a cleaning-oneself-off sort of thing. They don’t sit there for hours on end, lickity lickity (in my experience of ~7 female dogs.)
Scout, my shepherd/lab mix, had a close personal relationship with her butthole. I remember one time she was lying here in the office on the floor behind me. Lick lick lick lick lick lick lick lick lick lick lick lick lick lick lick lick lick lick lick lick lick lick lick lick lick lick lick lick lick lick lick lick liAAAAAUAUUUUUUUGGGGGGHHHHH FOR THE LOVE OF GOD STOP IT STOP IT STOP IT!!!
(She was clean and healthy back there . . . just making sure, I guess. We did not willingly accept her kisses.)
I think that some dogs are brighter than others, and can put together the sequence of conclusions required to “masturbate” as we think of it.
Other dogs are frankly too damned stupid. I’ve watched dogs of both genders give them a couple of licks, then look around like “Wha? What just happened?” Repeat a zillion times.