I can't remember the last time I used a hot glue gun for modelling, but I know some of you do. 99% of the time I apply craft glue through a Hypodermic needle, so this seemed a good idea to me, and the idea could be adapted to use on a squeezy bottle.
HOW TO MAKE a MODED GLUE GUN / Tutorial / DIY: 4 Steps (with Pictures)
Don't forget to put a pin in the end of the tube to keep it clear when storing though.