A story about shota** siblings practicing sex
The siblings are closely related.
Shota bought a smartphone and was looking at a game strategy site when he saw a naughty advertisement.
Then ○ri comes along and tells her that if she’s interested in naughty things, let’s practice with her, and they practice naughty things.
The setting is that they are twins, but as long as they are siblings, it doesn’t matter which one is older.
*The sample is a mosaic, but the text has been modified with black lines.