Another, lesser known name for a special person. Meant to be as offensive as the word retard. Though it can be used as universally as the word "fuck" such as "Quit being a such herp-a-derp" or "go be a herp-a-derp somewhere else". however the word can be butchered to be simply "herp" or "derp". Although some "herp-a-derps" will reverse the word and say "Derp-a-herp". Saying "Herp-a-derp" as a question changes the meaning to "A retard?" or "That Retard?".
"you herp-a-derp", "Herp-a-derp?", "What the Herp-a-derp?",
to have a devils garden is to have a vagina with genital warts. A Devil's Garden was a small boxed in minefield used in desert warfare. There is about 17 million unexploded anti-personnel/anti-tank mines, artillery shells, bombs dropped by aircraft, machine gun, small arms, and mortar rounds that still remain beneath the sand in europe.
"dude, that chick has a devil's garden", "Promote abstinance to keep people from having a devil's garden" (like that works)