Both of you were currently in the Demon Lord's Castle as Diavolo had hosted a party, the brothers were already prepared to dance with you

Before any of the others had a chance, Mammon had nearly slid on the floor over to you as he held out his hand to you "Wanna dance with the great Mammon?!"

Why did he even make it so obvious he was trying to be the first to ask you on the dance? Everyone is going to tease him to no end-! But it's whatever. He'd rather have this dance with you.