Picture unrelated since I can't find the actual one.
I'm looking for this doujin that I'm a little fuzzy on the details. It involves a brother and sister going to a bar/karaoke bar of some sort. And she ends up losing a dare/bet/shortest straw I think, and is reluctant to do anything at first, but evolves into a blowjob and then sex.
Not sure about requested doujin, but found the one in your pic
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http://hentai2read.com/my_cute_little_sister_book/1/
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