"Therian” is short for "therianthrope". It means a person who identifies integrally as a nonhuman being, such as a wolf, polar bear, or even earthworm. Now I must say by research that a therian is no related to a furry, Therians often define themselves as people who identify as a non-human animal, a definition which is distinct from that of furries, whose interest in anthropomorphic media does not necessitate identification with non-human animals.
No silly while you are either adventering or laying down Therianthropy does not require having a mask or doing quadratics (exercise on all 4's) you just are you, being a therian is not a choice. Its what I call it "The destiny of being yourself".
Therians don't just identify with animals; they identify as them. You may like (or even love) a specific animal or species of animal, but that doesn't mean that animal is your theriotype. In fact, a therian cannot choose their theriotype. You need to see it, while I took forever to land on a bear, I found out that it could be good like lets say your a fish, you would be a fast swimmer but also really not smart on not going to the deep end.
how to be a therian! "You must be born a therian" So yes, in a sense someone can become a therian, but they cannot choose to become a therian, as therianthropy is an involuntary identity. Becoming something involuntarily is possible yes, it's like being traumatized, you don't choose to become traumatized, but you still become it.
Some furries identify as therian and some therians identify as furries, but they do not represent the majority and should not be conflated for one or the other. So if you are a furry or a therian, with no tone deal with it. people will make fun of you or bully you but i know you can stand up for yourself. and oh don't tell a trusted adult, it doesn't help but if you do you don't have to tell them now, tomorrow, or at any specific date. If you don't want to tell them cause it scares you or gives you anxiety, then don't tell them. It's your choice. But you must also obey them when they tell you you can't wear a tail or any other specific gear.