I tried to find it.
Different search engines.
Nothing but a meme page without a comment about the sauce :/
Does anyone know?
>>15669018
it looks like satori komeiji from touhou.
>>15669141
yeah i was right.
https://hitomi.la/reader/443438.html#12
Koishi-Chan No Ecchi Na Hon Ga Nai Nara Watashi Ga Kaku Shika Nai Janai!!