World War II postal acronyms were first used to convey messages between servicemen and their sweethearts back home. They were usually written on the back of the envelope.
The acronyms, possibly including some more recent additions, are:
S.W.A.L.K. - Sealed With A Loving KissH.O.L.L.A.N.D. - Hope Our Love Lives/Lasts And Never DiesI.T.A.L.Y. - I Trust And Love You or I'm Thinking About Loving YouF.R.A.N.C.E. - Friendship Remains And Never Can EndB.U.R.M.A. - Be Undressed/Upstairs Ready My AngelM.A.L.A.Y.A. - My Ardent Lips Await Your ArrivalE.G.Y.P.T. - Eager to Grab/Eagerly Groping/Grasping Your Pretty TitsN.O.R.W.I.C.H. - (k)Nickers Off Ready When I Come HomeV.E.N.I.C.E. - Very Excited Now I Caress EverywhereB.O.L.T.O.P. - Better On Lips Than On PaperE.N.G.L.A.N.D. - Every Naked Girl Loves A Naked DickC.A.P.S.T.A.N. - Can A Prick Stand Twice A NightC.H.I.N.A. - Come Home I'm Naked AlreadyC.H.I.P. - Come Home I'm PREGNANTL.O.W.E.S.T.O.F.T. - Legs Opened Wide Enter Slowly To Obtain Full Treatment.E.D.I.N.B.U.R.G.H. - Erection Definitely Imminent Now Book Usual Room George Hotel.R.A.D.I.O. Romance And Delight I Offer (often used with B.U.R.M.A., Be Undressed/Upstairs Ready My Angel)Terry Pratchett parodied this briefly in his Discworld novel Going Postal. His acronyms included L.A.N.C.R.E. and K.L.A.T.C.H. (Lancre and Klatch being two locations in the Discworld), although these were never officially expanded.
A Dirty Pretty Things song is named "B.U.R.M.A." after the postal acronym and contains the line 'Be Upstairs Ready My Angel'.