Help remembering Yaoi title

I found this yaoi a while back, and all I remember from the plot is that basically the uke? wakes up one morning as a child. The seme's little brother abruptly comes over to live with them for a while. So they have to lie and say the uke is actually the child of a friend, and the uke has to pretend to go to school. One night when the little brother goes to the bathroom. The uke gives the seme a hand job, and the little brother overhears and thinks their brothers like a pedo. I might've confused whose the seme and uke, but one of them did get turned into a child,