a slanderizing of female genetillia referring to the curtian like appearance of the labia (majora). the "beef" comes from the flesyness of the vagina, meat is also used as a casual refrence to male genetillia "beat your meat".
"the beef curtians opened, she was ready to start the show."
Beefcurtian: Slang word for Vagina. The Lips of a vagina resembles the "beef" part. And the "curtians" part of the word is where you pull the vagina lips apart. So then thats where you get "beefcurtian"
Johnny pulled Sallys beefcurtian apart and licked it all night.