Mnemonic
Imagine this in your mouth. It’s one tooth that sticks out more than any other. It’s your fang. Can you see this sticking out of a wolf mouth instead? Try that if you can’t picture yourself with a fang this cool.
I don’t see the fang. Can anyone explain how you see the fang?
To be honest, not really. I just remember [that] = fang.
But if I had to guess what they meant, it would have to be something like this (roughly):
(I’m not even sure which stroke is supposed to be the fang 
)
Google gave me a couple results telling me it’s supposed to look like a molar from the side…
But I kinda like this picture better (stolen from google images)
Somehow looks like elephant tusks. An elephant heading left, including its head and front legs (or its lower lip of mouth?).
There is a pictographic origin, but not sure if it helps.
(But indeed, I just remembered that 牙 = fang.)
As for me, I view 牙 as “leaf” + “genius”:
才
Leaf genius invented fangs 
