Abbreviation for: you only live once, might as well make it tasty
used as a means to rationalize an inhumanely
high intake of unhealthy but delicious
foods or beverages: cake, ice cream, any 'all-you-can-eat' restaurant meal, etc...
Fatass 1: "Dude, you know ihop
Fatass 2: "Oh god... we shouldn't... but... yolomawmit."