You could always try psychology. Up the level for a little while and then anything you do in subsequent weeks will pale by comparison.
Change your diet to several pints of IPA (not before duty of course) regular baltis and any egg based products. You can then notch it up by utilising the 'cup cake method' of holding one's hand about 2" from the 'bombhatch' and trapping a small sample 'biscuit' to be deposited under the FOs nose. This can of course be accompanied by the warning of 'check that bad boy out!'
Soon you'll have 'em begging you to just fart normally.