tissue paper down onto the mailing tube and painted over it with the watered down glue. there will be lots of folds in the tissue paper but once you cover it with the glue mix it will be fairly smooth.
carefully paint the glue mix over the tissue paper on the end of the mailing tube. this will make the tissue paper a little stiffer so that it breaks rather than rips when the kids open it. make sure not to add too much glue mix onto the tissue paper as it may tear through if it gets overly wet. if it does tear through you can always just add another 