What does "fill up" mean in slang?

In slang, fill up generally retains its literal meaning of making full, but can have a few informal and suggestive nuances depending on context. In everyday slang, fill up can mean to eat a lot, as in fill up on junk food, meaning eat until very full. It can mean to drink alcohol heavily, as in fill up at the bar, though less common. In automotive slang, fill up means get gas, as in fill up the tank. In sexual slang, fill up can be used as vulgar innuendo referring to ejaculation, such as fill you up, which is considered crude and sexual, and should be used carefully as it can be offensive. In some regional slang, fill up can mean to become emotional, as in eyes filling up. In drug slang, fill up is not standard. Generally, fill up in slang is not highly distinct from standard meaning, it emphasizes fullness or indulgence. For example, in party context, fill up your plate means take lots of food. So in slang, fill up mostly means eat or drink a lot, get gas, or as crude sexual reference, with context determining whether it is innocent or vulgar.