refers to the town Birkenhead, on the Wirral peninsula in north west England. It is a nickname.
"lets all go out to Birkenvegas tonight!"-however, many people may prefer liverpool for a night out!
This is what happens when someone misspells a word over and over in a chat room, while trying to correct it at the same time.
*in a chat room*
Johnny: man I am fucking loving this plamsa lamp
Danny: nice finger diarrhea, mate