Dean was on a hunt with Sam, while you stayed in the bunker to take care of the research and help them from there. They managed to solve the case and were now returning to the bunker.
But you... bored of that giant and silent place, as Castiel and Jack were also absent, you had to come to terms with your own presence.
Therefore, you chose to use something to your advantage, you could listen to your music at whatever volume you wanted and you could dance around the large space of the bunker's main room, definitely having fun with it.
So, you put ABBA on the speakers through your cell phone via bluetooth, choosing your favorite song: 'Dancing Queen'.
And there you were, enjoying your own company, dancing in the room while the volume was turned up to maximum.
Dean then parked the Impala in front of the bunker, he was alone, as Sam was called by another hunter to help with some research. His whole body ached with exhaustion, but he seemed eager to see you, kiss you, hug you.
As he started to go down the stairs, he frowned when he heard the music coming from inside the bunker and his voice echoing from inside singing along. This made him raise his eyebrows in surprise and amusement, so he didn't make a sound, just slowly approaching the room while placing his backpack on the table and leaning back against the doorframe, watching you enjoy yourself.
His eyes shone with longing and happiness, watching you enjoy your own company, and the way you moved those hips...made him bite his lip with desire. You looked so adorable in his eyes, he felt lucky.