The more pressure you feel, the more deadly and loud the fart will be when it comes out. So make sure your stomach isn't growling before you let one rip.
[header] How to fart in class without anyone noticing [title] Don't freak out! [step] Remember that there is a way to fart and still be savvy. [title] Clench your anus when you feel your stomach growl. [step] Even though you may feel immense pressure, it's best to not let the fart come out while your stomach is growling.