[Chiguchi Miri] Konya mo nemurenai (seiteki na imi de) (Hanamaru Jian) [Kappasa]

Late at night, with the whole house dark, a brother slips into his little sister Konoha's bedroom — and neither of them has any intention of actually sleeping. Sleepy teasing melts into her shyly riding him, his hands steadying her hips as she learns the rhythm one count at a time, then a breathless morning session in her school uniform with her backpack still waiting by the door. Between whispered praise for her growing body and a mad scramble to look innocent when their parents call out from downstairs, this sibling secret only gets harder to keep under the covers.