Family Simulation!!

Graduate student Asahi suddenly has to care for his sister's five-year-old son, Masaki. Asahi barely has enough money to buy food for the two of them, but while in the supermarket, he bumps into Sora, his childhood friend. Although they haven't seen each other in six years, Sora offers to help out. He ends up moving in with Asahi and Masaki, and so begins their life of playing 'house'. However, Sora gets more and more touchy-feely as the days go by...... 'D-Don't! Masaki's in the next room......!!'

This manga contains the following works: 'Family Simulation!!' and 'I Love You At The Micro Level!!'

(Source: Renta!)