Wait, if he's a miniguy, then she isn't really a giantess, but a standard human sized one. Although it will appear from the miniguy and the viewer's perspective that she is indeed a giantess, she really isn't, technically. Now imagine, if she were to be a real giantess (building sized girl) and him being a miniguy (size of a fly), how would this doujin play out? Than again, she could be from another planet/dimension where they are building sized "humans".
But she is a giantess. She explicitly refers to him as being a human, which means she isn't human herself. He's a normal, full-sized man and she's gigantic.
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