A whomp whomp is when someone takes a compressed air can, like the ones used to clean the dust out of computers, and shoots the air into the mouth to get a "high". A good way to kill brain cells
Joe: "What'd you do last night, Rob?"
Rob: "Whomp whomps. That shit was so cash. I got high in less than two pumps. My head hurts like a bitch, though."
Whomp Whomp is similar to the 'Oh no, moving on' meme. When you say whomp whomp you mean it in a way that you don't feel sad/sympathy to another's problems. Although upon using this you might get jumped
Person A: "My grandma just died! She was ran over and then eaten by a pack of wolves when she was still alive!"
Person B: "Whomp Whomp"
Person A: "KILL YOURSE-"