One of the first things to understand and appreciate is that not everyone needs to know or that they need to be part of or involved in. The matter itself is already a very private thing and it should be carefully weighed where, when, and how it is shared with others, if ever at all. The world outside, particularly in public and among the general populace, is probably the place one should want to be most careful, a school included. Being different, at all and for any reason, is going to attract negative attention and get no shortage of heckling. Being overtly different, such as by wearing a tail, is going to amplify that.
So what is to be done?
Foremost, tell them to leave you alone, that you do not need to answer to them, and give them a consequence if they do not. Tell them that you will tell a teacher, counselor, or principal, that they are harassing you, and that they need to leave you alone. If they continue, do not hesitate. Do not antagonize, argue, confront, debate, or interact with them, instead go directly to someone you trust who will address it. Do not stop there, write down every time they do this, when, where, how, what happened, the time, and similar, keeping a report of it. Turn it in to the person you trust so they can show the people they need to.
Second-most, weigh one's options about how one shares and conducts themselves. Wearing "gear" is a notoriously overt way to garner a lot of infamy because it is so obvious. It might make one feel more complete and expressive, more true to themselves, but that might not actually be true at all. Is that one thing worth having people who legitimately do not and will not understand heckle constantly over? Probably not, consider things more subtle, be them jewelry such as necklaces or brackets, but keep them subdued and not flashy but
meaningful. Accept that if one is going to wear something like a tail to express themselves, it is going to affect the way people will interact and behave, with nothing about that capable of being changed. Be smart, weigh the options, figure out what trades can be made and what can be put up with.
Third-most, having a theriotype or being otherkin does not make a person a psychopath. If anything take heart in the fact they understand everything so poorly they cannot even name-call correctly. Remember that these are just words so they only have power over you
if you let them. Roll your eyes and ignore them, show them nothing effects you about this. If they cannot get a rise out of you with words, you take away their largest weapon. But do not forget, they
cannot touch you, and if they put their hands on you in any fashion not approved of, do exactly what I suggested earlier of immediately going to someone who can do something.
I hope that this proves useful,
@kyro. This is the most basic advice I can lend about dealing with people and in general. It might not be ideal but neither is the situation and neither is the way people treat us for being ourselves when we are doing no harm to anyone.