adding to the pile
The act of taking a massive dump inside a toilet that is already clogged with a massive dump that someone else previously took.
“Hey, Jack did you unclog the toilet?”
“Nah, dawg I was just adding to the pile!”
“Nah, dawg I was just adding to the pile!”
Adding pennies to the pile
Adding or contributing a small (usually unnecessary) bit extra.
When John decided to help out the cleaning by taking away his rubbish from lunch, he was just adding pennies to the pile.