a poop so big that it makes a thunderous sound. People who take a thunder dump, or TD, tend to feel a splash of water on their butts afterwards.
"Wow! I just took a huge thunder dump and now my butt's all wet!"
to give shock knowledge to someone, to shock them with your information, to enlighten them with new information
"I will lay down some thunder dumps on you." "Here is a thunder dump for you"