Usually Aunt's are side characters in what we call Life Sims. The only one I can think of that does exactly what you ask for is the Visit, linked above.
ICCreations has a few games that involve the Aunt, and they were entertaining enough, but because they don't focus on the aunt it's not like she's guiding you or anything. Just search that name and you'll find all the projects they've worked on.
I wouldn't normally suggest this game, but, I do have to say that Aunt Kira is probably one of the better examples of an Aunt in a Life Sim acting as your guide, so if you haven't played Big Brother, it's probably good for your particular kink.
This story is just getting started, and it's not gonna be so much of a teaching experience, but I really like where View of Family is headed with the Aunt. The game just came back from being on hold. It's one of my favorite life sims.
This last one, Sister Sister Sister, barely deals with the aunt at all, and not sexually last I checked, but it has the other half of your kink down pat. In it, rather than the Aunt, your older twin sisters are teaching you, making use of the women around you, your neighbor/twin sister's best friend, your twin sister, your mother, your cousin, the neighbors mom, the girl who didn't pay attention to you in shcool, etc etc. It uses hypnosis so if you don't like that then don't play it, but otherwise it's got ok sex. The dev is also bad at code and branching it seems, so sometimes the characters don't acknowledge past events.
