meaning Closet Dirty Girl for Life. this can connect to DGL or just DG, both involving dirty girls. but the C in CDGL is the key aspect. the C meaning Closet means that the girl is a DGL or dirty girl but very few people know because she is secretive about it. hence the word Closet.
Charley- "So i heard you macked it with a couple of guys over the weekend, i didn't know you were a dirty girl"
Brenda- "I am so not a dirty girl!"
Charley- "Oh my b your a CDGL, always keeping your dirty side a secret."