another acceptable translation is gas. as in after you have a large meal of bean, cabbage and cheese. this is where the no-touch throw stuffs come about. it's deadly at 10 paces in enclosed space. the counter for this ki is to open all the doors and windows, might want to kick in the big fan too. but whatever you do, DO NOT light a candle or use any sort of open flame!
have you ever wonder why we wear the hakama? it really is a device to contain and slow dispersing the ki leak during practice; thus the two big vents on both side of the hips.
I trust this explanation comes from years of serious study without any damage to the tatami ?
Made me laugh anyway, I hope we both can be forgiven for having a sense of humour ?
Co-author of `Positive Aikido`