They're not related by blood and were in the same class in middle school before the step-sibling situation, this is not incest at all.Ahh yes, the only way to return to a follow I barely remember. A chapter spoiling what seemed to be a bit of fluff family time with surprise incest
I think she's being intentionally misleading than lying tbh. When she says slept I think she literally means slept but phrased the two things to mislead and get a rise out of her, or to show some sort of superiority like losing heroines always doOh, fuck off, you lying slag.