It is a unique tire iron. Although unique and therefore more damaging than a normal tire iron, it's still not a highly damaging weapon, but it does have a rapid attack.
Sitting on a shelf in Dominic's and Machete's house in Canterbury Commons. There is no karma loss, nor is the reticle text red, so the weapon is perfectly fine to take.
Behind the scenes[]
A "(insert profession's) friend" is a fairly common way to refer to that profession's most-used tool. See, for example, "plumber's friend".
A highwayman is a robber who preys on travelers, although in this case it is likely also in reference to the Highwayman vehicle obtainable in Fallout 2.
Bugs[]
Xbox 360 Sometimes the weapon does not appear in game.
Sometimes the weapon does not appear in game.