One leaves the house to go out, and then leaves the original spot and goes to another location that is further out.
Etymology: Legend says that a man exists who is so awesome at partying that he goes out every night and not only does this mysterious gentleman go to one destination, he continues going out and doing even awesomer and awesomer things. There was a great need for a verb describing this man's legendary partying ways. This word is "further out". There are also rumors of an awesome woman who's partying ways put this man's going further out to shame. She is said to leave the stratosphere when she goes out.
That man is such an awesome drinker he doesnt just "go out" he goes "further out".