When a sheet is hung from the upper bed on a bunk bed, the lower bed is obscured by the sheet, thus creating a fapcabin.
Ben- "What are you doing?"
Ryan- "Hanging a sheet from your top bunk bed."
Ben- " Ohh okay. So you're making a fapcabin!"

Later that night-
Ryan- *fapfapfapfapfapfap*
by lordwhoopass April 6, 2013
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