This exchange can be found in the replies that the artist received on twitter:

Fan:
１枚しか着てない。つまり(ぬいでどうぞ)

Runawate56:
（1枚脱いだら大変なことになると切ちゃんはまだ気がついていないのだ‥‥）

This translates to the following.

Fan:
She's only wearing the one layer. That is to say, (go right ahead).

Runawate56:
(If she sheds that layer it'll be a sight to behold, but of course Kiri-chan will remain unaware of it....)