why would something need a counterpart to be feminine or masculine tho? it's manly or womanly qualities not the qualities of the counterpart
They need a counterpart to be feminine/masculine for a reason.
A woman can't have a snake feasibly. What they do have, however, is legs, a torso, arms, and a head.
A man can't have a vagina feasibly. What they do have, however, is legs, a torso, arms, and a head.
You can't describe a feminine snake. Women don't have them.
You can't describe a masculine vagina. Men don't have them.
There's nothing to base masculinity or femininity off of, therefore neither one can be the other, and feminine snake doesn't exist.