This topic has been going on for a while now and even longer in your life and I am here for you to tell you that it is also haunting me as well because I am guilty of that sin too. I won't go into much detail and only want to say that the animal was not hurt nor traumatized, it was only me who was hurt and traumatized emotionally. actually I didn't really do it but I tried to do it and that is as bad as doing it.
Anyway, the damage has been done for you and for me and there is no way on earth that we can take our sins back.
But I want us to ask ourselves intensively why we feel bad about things we do. Why do we feel guilty when we have commited sin?
It is because we broke a law. We broke a human law but a human law was constituted indirectly by god as apostle paul wrote : 'for there is no authority except that which God has established” (Rom 13:1)' (among other passages).
So do you see that your submission to the government is indirectly a submission to god? and so: to accept the punishment of the state is to take the just punishment of god for our wrongdoings. So if anyone would accuse me of the law that I broke, I would gladly take the penalty and pay off my guilt.
How is the legal situation in your case? Have you really broke any law? From what I read oral sex from your pet is not breaking a law if the animal doesn't suffer. In my country germany, it is forbidden but only if the animal is forced and not harmed.
In fact, as I write this post, I have made an appointment at the police station and I am going to tell them what I did and then I will see if I get a penalty or not. It is going to be really hard to go there, I think it is the hardest thing I've ever done, but I'm doing it. I have to go through this shit to get my life back and to get a clear concience again. Actually what I fear the most is how they look at me or that they will laugh or make it public somehow. Not so much a money penalty (which is the highest penalty I can get). But this embarrassment will not kill me.
I have also confessed it to a good christian friend and even to a non christian friend. And both were very friendly and loving to me and still are. they care about me and want that I feel better in my life again.
So what I want to say to you and to everyone else who commits a crime is this: do something, go to police, tell your good friend, go to a priest, go to a therapist. It is the only way to get out of this shithole that we have dug ourselves in, of that I am sure.
thank you for confessing in this forum and opening yourself.
I wish you the power of jesus christ to overcome the devil and to 'overcome evil with good' (romans 12:21)