Quote Originally Posted by Lampada View Post
Ииииии... Так это калька с английского. Да, лучше избегать употребления этого пошленького выражения.
Да, согласен. "Булка" в данном контексте = buttock. "Шевели булками" means "stir you buttocks" or "move your ass" whatever you prefer. At the most decent sense this means quick action but nevertheless sounds [a bit] rude. I heard this phrase spoken out by brigadier on construction site (in Russia of course).

In addition, another version of this phrase exists: "шевели колготками" (move your stockings) and used mainly by or towards a woman. Pretty rude though.