Short form for "Stifle Until Shit Flies" (out of your nose). A softer, quieter version of "LOL" in the internet world. While cruising online at the workplace, professionals, ie: bank managers, sometimes come across humorous information online and can't laugh out loud at the risk getting caught by co-workers. They simply SUSF (stifle until shit flies), and hope no one notices them painfully holding it all in.
SUSF exporting levels from the nasal passage may vary depending on cold or sinus conditions.
1. While scrolling the thread, Gord noticed the picture posted from Newfoundland and immediately began to SUSF, desperately hoping his colleagues would not notice.
2. "Thankfully I didn't LOL, but I sure SUSF'd hard when I read that", Ricard commented to Pauly.