It's really peculiar how people seem so very stuck on the idea of all female creatures possessing mammalian reproductive features. Basically what you're saying with this is that you simply will not let go of the sexual appeal in favour of being biologically accurate.

Something being "fantasy" is not a valid reason to completely disregard biology. I would be fine with backing up this claim if you provided me with actual scientific reasons why a female Naga should possess mammary glands and breast tissue.

I.e., are they actually mammals that simply possess a scaly outer shell, and legitimately feed their young in the same manner as humans do? Or are they a part of a completely different phylum altogether that also happens to manifest this trait.

I need more concrete facts to accept this. One picture of someone's OC, who adheres to their un-explained opinion, is not a legitimate argument.