A Necessary Fuck. One that is required either arising out of circumstances beyond the control of the participants or due to an extreme sexual attraction that can only be settled with a good toss in the sack.
Etymology>>> Sex ( the act of penetration) + essary (required or obligatd)
A Shackteau is a humble, weather-beaten, structurally questionable shelter located in a spectacular or highly coveted place—Wales, Jackson Hole, Sun Valley, Crested Butte, coastal Maine, the Alps—where the building itself may be worth almost nothing, but the dirt, view, access, and mythology make it absurdly valuable.
In use:
Shackteâu - We thought it was an abandoned shed until the realtor called it a rare alpine Shackteâu with unobstructed views and listed it for $2 million.