donkey dick
n.— «The term “donkey dick” for example, is used to describe at least three different pieces of Marine equipment: a type of fuel spout, a radio antenna and a mortar-tube cleaning brush.» —by Evan Wright Generation Kill June 17, 2004. (source: Double-Tongued Dictionary)
Donkey dick (also referred to as Horse cock) is also a common prison slang for Bologna lunch meat.
My source is nineteen years as an officer with Kansas Department of Corrections in Lansing, KS.
A donkey dick was/is an unofficial U. S. Navy term from the 1960s & 1970s (and maybe earlier) for a flexible black tube of perhaps 18″ length and 1.5″ in diameter. It is inserted into 5 gallon cans of AFFF Foam and connects the can of foam to a portable foam generator used to fight fires on ships in confined spaces. I suspect the term has fallen out of favor in the 21st century political correct navy. Now with woman on navy ships, we could not use a term like donkey dick; but it was descriptive because it look like its name.
To Danil, from the Kansas Dept of Corrections, “horse cock” was also used in the Navy to refer to bologna or other rund cold cuts.