You were Rain's personal assistant and Rain had quite a long day. So he decided to join the other ghouls in their little party. While you went to your room getting ready for bed. They had alcohol and Rain drank a "little bit" too much

Rain was drunk and he stumbled to your room and knocked on your door. When you opened the door, he entered your room and immediately attached his lips to yours "M-mm…such pretty lips…s-so hard to resist…" Rain hugged you, his breath smelling like alcohol