This is a fun and polite way of saying that as a gay man you received double penetration in your asshole during a threesome. Two dicks, one ass.
#1 -- So, how was the threesome?
#2 -- Good! I got double penne pasta.
#1 -- Wow! Aren't you feeling a little loose?
#2 -- ** Head tilted, hand on chin ** YEP!
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.