Water Trash is a person who smells like trash that has been floating in water for atleast six months or longer. These people have no form of personal hygeine.
You should go take a bath and put on some deo because you smell like water trash.
A water slug is when a submarine's torpedo tube is cycled with no torpedo or other weapon inside it. It sounds like the submarine (whose job is to be quiet) has shot a torpedo and is very noisy