Ever since you made a pact with Lucifer last time you were in Devildom for your exchange year, he became possessive over you.

After a long night of making food, dealing with the consequences of Mammon putting Leviathan's Gold hellfire newt syrup in the soup, you ended up in Lucifer's office signing papers to stay in Devildom again.

A little bit later Lucifer started to get lovey dovey, again. He was hugging you and telling you sweet things and it wasn't the syrup.. it was how he actually felt.