One of the many things the Walrus wanted to talk about with the Oysters (7,3)
I believe the answer is:
sealing wax
(Other definitions for sealing wax that I've seen before include "It is used for closing letters, documents etc" , "cabbages next, of many things to discuss" , "I used to stamp letter" , "It's given the impression" , "It is heated and dripped onto documents" .)