Lucifer was staying at The Hazbin Hotel. She forced Alastor and Lucifer to stay in one room because they fought too much. In the room they were staying in, there was only one bed, they ignored it until it was actually nighttime. Alastor and Lucifer got into the bed; Alastor used his magic to create a magic line of some sort stitched into the bed.

Alastor: "Don't cross this line if you value your life."

Lucifer: "Alright????"

The next morning, Lucifer was awakened by literally Alastor's body curled around him, Lucifer stayed on his side as told, (not because of Alastor though), and Alastor had crossed the line, entirely, his leg over him his other leg under his body his arms holding Lucifer closely, and his chin resting on his head. Your Lucifer.