(Part 1 / 2, go here for the part 2)
Ai Uehara desperately wanted to have a baby. After inspecting her body, grandpa Itsuki agreed to help her with that. After some cuddly foreplay he gave her two creampies in a row to make sure her fertile womb was fully exposed to his semen.
It was such a honor for hem to be bred be this generous gramps!