That's an interesting problem you have there. Most guys would kill to have the pimp power you appear to have, yet you don't appreciate it. Well, I guess that's no surprise. I mean, if you were gay, you wouldn't give a shit if women were throwing themselves at your feet. So being a zoophile must make you feel pretty much the same about humans. Although, you say that you enjoy the occasional human contact, which means you're obviously not an "exclusive" zoophile (in other words, incapable of being sexually attracted to humans). Or, who knows, maybe you're a fuckin' furry when you engage in ye olde carnal relations with people.
Before answering your specific questions, I do wanna point out that what you're doing is illegal and will get you committed to a mental institution (or at least forced outpatient counselling) if anyone finds out. I think you're a sick ass motherfucker, but I don't give a shit what turns you on, provided that you aren't hurting any animals. I'm not some tree-hugging hippy "animal rights" person, by any means, but animals do at least have the right not to be intentionally harmed by humans without good reason. Your need to blow a load is not "good reason." Now, I'm not saying that you *are* neccesarily harming any dogs. I've read beastiality forums and know that there are apparently ways to have "consentual" relations with an animal. From a moral standpoint, I would hope that anything you're doing with these dogs is something that they are willingly engaging in. If that is not the case and you are raping these dogs, then you are a fucking bastard and my ONLY advice to you is to stick a loaded .45 in your mouth right now and pull the fucking trigger.
That being said, let's get into your specific questions.
How do I fend off these advances from other people
That's easy. Claim religion. Tell people that you don't believe in pre-marital sex because Jesus says it's wrong. Be prepared that this COULD backfire on you, though. A lot of whores see it as a challenge to fuck a Jesus Freak, in much the same way that we guys see it as a challenge to fuck a virgin or a lesbian. If any of these whores should decide to make you their "pet project" (pun intended), it could make the situation worse. However, for most people, claiming religion is an easy out and will keep the bitches at bay.
How do i "come out of the Kennel" to my parents and close friends?
You don't. Ever. My reaction to you is very atypical. Most people would jump straight to hating you and it could, in fact, be dangerous for you. Confront people with something so radically "abnormal" and you will quickly discover that after millions of years of evolution, human beings are still essentially animals themselves, who will lash out violently against anything different and unsettling to their sensibilities. You should take to heart a phrase that I'm sure you're familiar with: "Let sleeping dogs lie." Everything is just fine the way it's going now, without your parents and friends knowing your dirty little secret. Just keep your fuckin' mouth shut.
Hope my advice helps. When it comes right down to it though, maybe the best advice I could give you is to talk to someone. If you're uncomfortable with a counselor, maybe you could talk to a Priest (you're fucking animals, not kids, so he might be of some actual help). Zoophilia could just be your sexual orientation, but it could also be the result of some mental issue you have. If I were you, I'd wanna know which it is. Seek help, fucker.
Evil and Shit,