Alas with the age difference it's not to be. :(
I've seen two online where the dad goes back in time and screws his son. And both times I wanted to barf. The sad thing is that in one of them, the art was beautiful and the story nice and I kept hoping it WAS NOT his son (that the wife had actually gotten pregnant from some other guy). But alas, it wAS his son. Ruined it totally for me. Totally. Uck. Ick.
This is not the time machine one (that one a scientist goes back). BUT...this is teh one I was saying was nice until the incest was confirmed. (My hopes died.) I'll never read it again. Too gross for me.
http://www.mangago.zone/read-manga/not_equal/
if i knew this hyung before i'd fkin ship him anywhere with anyone
come on next to this hyung everyone is pretty much shit