As much as I hate to sound so harsh, as I believe you’re just naive and thinking with your pants rather than your head, but I would not go through with this if I were you. There’s a big difference between having sex with a dog you love, know, and trust, and having sex with a dog you don’t know anything about, especially if it’s a stray.
That dog has no home, he has no family to love and care for him, he’s stuck sleeping outside even when there’s bad weather, he has to search for his own food, clean his own fur (which dogs aren’t very good at in the first place), deal with bug bites, rude people that probably throw shit at him just for existing, etc. And if he were to go to the pound, he’d likely end up killed, so he’s S.O.L. And instead of helping him out and finding him a home, you wanna have sex with him, despite the fact that you barely know this dog, and don’t know how he shows discomfort, if he could potentially bite, etc…Do you see the problem here?
If you have to ask all of this in the first place, chances are you shouldn’t be going through with this. And if you don’t know the answers to these questions, how the heck are a bunch of internet strangers gonna know?
One of the key aspects to consensual sex with an animal is knowing their language so you can determine if they’re actually consenting, if they’re comfortable, content, in pain, discontent, etc. If you don’t know this dog, you don’t know his language. And I don’t know if you know this, but first times seldom go perfect, as both you and the animal tend to be inexperienced. For both of your safety, it’s best if you do it with a dog you know well. They may not have horse dicks, but sex with dogs can be pretty painful too, and the biting and scratching can be offputting for a first time. In some cases, It can be dangerous. Do you even know if you’ll be able to fit his dick in you? Cause if you underestimate him and he ends up being too big, you’re looking at a trip to the ER and some fucked up genitals. And if people found out he hurt you by scratching and biting, guess which of you is getting put down? This is the real world, not a porno. Interspecies sex isn’t as safe and easy as many would like you to believe.
And look, I’m not saying you have to take this dog in yourself, but the least you could do is post his picture around and look for someone willing to take him in, or you could at least offer him food, water, and even just a flea collar while he’s wandering about rather than sex. Cause I’m pretty sure those are much higher on the list of things mammals need to survive than sex.
Look, you seem pretty young (I hope you’re at least 18 though or else you shouldn’t be here), and you said yourself that you’re an amateur. I’m glad you at least asked before pulling through with this. I now implore you to please take this advice, and don’t touch that poor dog. He’s got enough on his plate as it is.