A glutton or a fat person. Derived from Vitellius, who was both a glutton and a fat person, who was Emperor of Rome in 69 A.D. and whose short reign was notable only for his incredible gluttony. Vitellius was an obese glutton who was notoriously lazy and self-indulgent, spent most of his time as emperor eating at luxurious banquets four or five times a day, all paid for with tax money. He would send the Roman Navy to procure rare foods for his banquets.
For context, Tyler Vitelli is a popular comedic content creator on YouTube who posts stories detailing his strange and silly experiences.
At one point in his career, people have started to comment "Oil up." under his posts. It is unknown why the general population uses this phrase, but it has a big impact on him, as he came forward and made a video telling people to stop commenting the phrase, as his family also watches his videos.