When you fart in bed, typically on your back, and your fart echoes throughout your mattress. This does not work with memory foam mattresses; only "hollow" spring-based mattresses can resound the fart. (Abbreviated from mattress reverberation).
To compound the dutch oven effect of farting in bed, I farted with my ass to the mattress, making sure I got plenty of mattress reverb. The resounding effect made the fart so loud that it woke up my girlfriend.
by ILL203 November 04, 2010