Many people like using pi tapes to measure the pipe size. Pi tapes, which wrap around the pipe the same way but have units in diameter, can be expensive. With calculators everywhere today, dividing by 3.14 is a snap, making these pi tapes not even necessary.
Fuck is an obscene English-language word, which refers to the act of sexual intercourse and is also commonly used as an intensifier or to denote disdain. Its origin is obscure but is usually considered to be first attested to around 1475, although it may be considerably older.
This is US military slang meaning a chaotic or out-of-control situation ... similar to cluster f*ck or dog f*ck/pooch screw or SNAFU. The basic form is goat f*ck in the sense of a goat-f*cking event, thence goat rape and the euphemistic goat rope. The participants in a goat f*ck are pictured as engaged in useless pointless activities (such as copulation with animals) rather than in purposeful activity, I suppose.