This one manga about this girl and her little brother. THe girl is in high school and gets taken in by the teacher who used to be a delinquent has a full winged tattoo on his back.....I think she gets married to him or has to act like it. I think one scene had her leaving the house but the kid was dropping candy for the teacher to find them.

Sounds like Kiss yori mo hayaku 🙂

"Things that are evil in the light might be good when done in the dark"