A portmanteau of the word Hikikomori (a Japanese word used to describe people who isolate themselves and lack a social life) and the acronym NEET; "Not in Education, Employment or Training."
"Get offyour ass and go look for a job! Quit being such a hikiNEET."
Sneak away to meet your mistress. ("Hiking the Appalachian Trail" is the first explanation of where South Carolina Gov. Mark Sanford was when he disappeared.)
"Has anyone seen Jawann? I've been calling and texting him for three days and he's not answering."
When in the act of having anal sex with your partner, you say you have to pull out for a second (to put on another condom or some other reason) then your friend switches in and starts having anal sex with her while you sneek around outside and wave at her through a window. then when she turns to look who is having sex with her your friend punches her in the face and at the same time you punch through the window.
To be unfaithful to one's partner e.g. in an extramarital affair. Named after South Carolina Governor Mark Sanford, who was said to be hiking the Appalachian Trail, when actually he was visiting his mistress in Argentina.
"My husband has a lot of "meetings" and "conferences" to attend to lately. I think he might be hiking the Appalachian trail."