+1 to the movies + straws.
i found something that surprisingly worked pretty damn well, but it did restrict the draw a bit, but not enough to bother me.
ok, i got some crappy webcam pics, so bear with me.
this is the stem to my Nakhla Egyptian rig, size comparison with my thumb
then, i take the old purge valve from my chinese rig, which has 3 holes along its circumference
then i sorta just shove and twist it in, till it "sticks" it doesnt go in, but it stays there and seals. then, voila, diffuser