I got to thinking the other day what would happen in the these doujins if Yuuichi's parents came to visit and caught him banging Akiko. But then I remembered that we never actually see his parents.
If I remember correctly wasn't Yuuichi's mother Akiko's older sister? I wonder what she looks like. Maybe she is one of those loli mothers like Hayase Kinue from Masamune's Revenge.