Strange bumping noise

[floydzeppelinfan]

For the past week, I have heard a bump in the back of my car. For example, I will go over a speed bump, and I hear this thing hit the bottom of my car. It sounds like its a little behind the rear passenger seats. So, I get out of the car today, and I pushed the car down from the back. I hear it, and I can hear liquid moving in a tank and also something is sqeaking. Some people have told me it is the rear shock mounts, however I have no idea what those are and how to fix it. Any help is appreciated.

[El Presidente]

Well, if you look in the thread I just made, the last two pics show the RSMs. Overtime, they deteriorate inside. You can either replace them yourself, which isn't fun but can be done, pay someone to do it, or live with the bump.