If you're around others and one gets loose, don't overreact-in fact, don't react at all. This is the opposite of what most people do when they accidentally leak one, so a strong display of ignorance will point people's suspicions another way.
[header] How to act like you didn't fart [title] Don't react to it. [step] This is rule number 1. The surest way to let everyone know it was you is to immediately look worried or ashamed.