My Navy coffee cup

So here's a joke I heard in the early 70's about Navy coffee cups. This was supposed to be "true" which makes it a "sea story." Know how you tell it's a sea story? It starts out "And this ain't no ****."

So, "I was told," (by someone I forget)...........

"I knew this ET Chief, was pissed because people kept using his coffee cup. So one time when he's ashore, he bought another one just like it and put in his locker. Next time he was "on" he goes into the coffee mess, gets his cup, and goes into a big deal a bout people stealing his cup, so he takes it out, rubs it all over and inside his coffee cup and zips it back up, fills up his cup, and says, 'now, let's see you clowns use my cup again.' and walks out.

Goes out on deck, heaves that cup over the side, goes down to his locker and gets his new cup, goes down to some OTHER coffee mess, refills his cup, and casually goes back down to his own."