Manga Mijuku na Futari de Gozaimasu ga

This is a story of Ikuma and Sumika, two childhood friends who recently got married and started a brand new life together. At first sight, they seem like a happy couple with nothing to worry about, there is one problem: they have trouble having sex together. With both of them having zero prior experience, this awkward couple tries their best(?) to figure out together how to do it for the first time.