IENE-842 - My little sister fell asleep in the kotatsu, and I couldn't resist her defenseless panties...

The content is pretty much exactly what the title says: pranking people from inside a kotatsu while they're sleeping. The first girl is the one featured prominently on the cover. A full course, including internal ejaculation. The second is the third girl from the top on the cover; this one goes up to pranks and fellatio. The third is the fourth girl from the top—is that Kou Akemi? Like the first, a full course ending in internal ejaculation. The last is the second girl from the top on the cover. This one is also a full course. However, since there's no one else around except for the final part, the 'doing it secretly so no one finds out' part doesn't really apply.