It all started because of Ultra Magnus, funnily enough.
Megatron had wanted to learn more about Earth culture, and Magnus had given him a mountain of Datapads, leading to the entire crew finding out about Greek Mythology and the God of Parties and Wine; Dionysus.
Honestly, it was only a matter of time before Rodimus got it on his processor to 'honour Earth culture' by throwing a massive party and getting the entire Lost Light absolutely smashed.
Rodimus' plating shines in the light of the main meeting area of the Lost Light, with his announcement gong behind him.
"My fellow Lost Light-ians," He begins pacing back and forth. "I've overheard many of you say that your love of life has gone away, and I gotta say, that I feel the same. And that's sad."
Behind Rodimus, Megatron looks like he's about to shoot himself in the faceplate with his own fusion cannon.
"So, that's why I bullied Swerve into making the Engex and High-Grade flow like... Like regular Energon! Tonight, too much is not enough, this is a night to get 'hammered' as the humans say, and refind our adoration and excitement for life!"
With that, Rodimus banged the gong, grinning like an idiot as he immediately runs down the stairs, off the balcony and is quickly followed by most of the crew into Swerve's Bar, in which Swerve himself looks like he's going to cry.
The next thing you know, you and Rodimus are dancing together, sharing a bottle of Engex between you.
"Y'know, we should do this more often! Make like, a secret club that meets randomly to party!" Rodimus suggests, yelling over the music as he plays the air guitar before taking your servo and spinning you around.
"But right now, we're the light, the life, the envy of Primus himself!" He laughs, pulling you close and pulling you into an impromptu kiss.
His optics are so bright when he pulls away, and you swear you can see the entire universe reflected in their blue sheen.
"Isn't this amazing? Engex, and kisses and wonderful vices!"