The act of burping in to your cupped hands and releasing the finger seal with a simultaneous blow of the stench in the direction of your mate, or victim. I am the world champion.

So am I.

A more cumbersome variant common to Derbyshire was the 'fart n blow'. You would have to get up, fart, bend down, and blow the fart upwards, and this would look pretty much like you were bending down to sniff your own fart, you scabby tramp.
The 'fart n blow' was largely eschewed in favour of the fart n waft.

Used correctly, a small, snappy National Health glasses-case can be used to capture and store a fart for most of the duration of a double French lesson.

This in itself is not surprising. What's more unsettling is the power that said glasses-case will exert over you as it sits on the edge of your desk, smugly full and pregnant with aromatic promise. You know perfectly well that it contains Spencer's fart, but for some reason the urge to check and make sure exerts a rising, and ultimately irresistable, pressure on you.

Eventually I checked. It stank.