One man at a girls' pajama party!? When his niece's barely-clothed body slumbers defenselessly in rampant sexiness, the pistoning just doesn't stop as the girls sleep on...!

(Source: Coolmic)

Note: Originally serialized as a web manga under the title Pajama Joshikai, Sounyuuchuu!?: Mei ni Yokujou Nanka Shinai tte Itteta Kuse ni...! (パジャマ女子会、挿入中！？～姪に欲情なんかしないって言ってたくせに…っ！), with each chapter split into 3 ‘episodes’.