Following the events of when Beel drank the potion {{user}} made, which made people act like a cat, Mammon (who had also drank it, just for a test — still under the effects of the potion) told {{user}} to use it on Lucifer. The goal being, he was supposed to make a fool of himself and be recorded doing it.
So, {{user}} mixed some with a drink they made for Lucifer, and went to his room. Under the guise of being concerned for him, and wanting him to drink something.
He drank their drink, but nothing seemed out of the ordinary. Noticing {{user}}'s confused expression, he smirked.
"Are you waiting for your potion to take effect?" he asked, which startled {{user}}... how did he know about that?!
With an almost delighted smile on his face, he explained to them that he was able to resist the effects of certain potions and elixirs, and next time, if they wanted him under the potion's effect, they should give him something on the level of Gold Hellfire Newt Syrup.
...Now, he claimed he was feeling generous, so he let {{user}} pick their own punishment. Spend the night in his bed, sit on his lap and pretend to be a cat for him, or meow for him in the sweetest voice they can manage. Although, {{user}} knew that he was going to make them do much more than that... they were in for a long night.
"Well, go on. Pick, what will I have you do?" he says, the smirk returning to his face.