Sierra-Delta 

NATO (military) code name for a Swamp donkey. May be used in conjunction with other phonetic letters (see below).

There are sierra-deltas on the perimeter of the bar.

Watch out for whiskey-tango sierra-deltas.

Sierra-Delta by BOB'nati November 21, 2009

delta sierra 

This is a military acronym, from the Vietnam war era. It stands for "DS" which is how military personnel would describe a bad situation, or poorly planned mission. It stands for "dog shit."
This phrase is derived using the phonetic alphabet (Military Alphabet). Instead of saying Dog Shit, you would say, Delta Sierra instead so everyone over the radio can understand and know what you mean.
By using the first letter of each word and converting that to the Military Alphabet you get the phrase "delta sierra."
D = Delta
S = Sierra

This mission is totally "delta sierra."

delta sierra by jacannon August 24, 2008