I love talking about this stuff. I'll post some videos on it soon as well:
Mastication is the common practice in Tanna, but nobody would ever think of chewing dried powder. That just sounds like a terribly bad idea. It is chewed in fresh, whole form in order to break it apart so that it can be squeezed and strained. Once it is dry and powdered, there seems no point to chewing other than to punish yourself.
Usually, the mouth is very full of kava, and it is open for expiratory breathing, resulting in (what many Westerners would consider horrifically gross) a constant 'chorus' of throaty noises, rather than keeping the mouth closed and breathing solely through the nose. I was told that actually produces less saliva - because chances are it will be consumed by someone else present - so it is pretty moist afterward, but not as full of spittle as it could be. Each small-fist-sized pile is generally used to make about 2 shells of kava. (Remember though, it is fresh kava, so it is not like a small pile of dry kava, as it has more water-weight.) While all the men can participate in chewing, only virgin boys are actually allowed to touch the chewed kava with their hands to squeeze it once is has been expectorated. Then, the chewed pile is placed in a coconut fiber cloth (Or in burlap, or something else if that is what they have available) while water is poured over it, and squeezed into 2 shells placed on the ground below it.
You do not get anything of a buzz out of chewing it, but you do get a terribly sore jaw for the first several days if you are not used to it.
The strength is phenemonal:
One shell, and you are good.
Two shells, and you are pretty wobbly.
Three shells, and you are likely cross-eyed, and would have difficulty getting back to your hut without staying put for a while.
As soon as someone drinks a shell, everyone pipes down up out of respect for the kava, and the drinker. No clapping. No shouts of "Bula!" No hip-hop music. Nothing they do in the South Florida bars. (Sorry guys, it is frickin' LOUD down there!) Just peaceful serenity by a fire in the darkness with the volcano glowing and rumbling in the distance.
A couple other things about the Tannese traditions: You must have a fire present before any kava can be chewed and consumed at evening nakamal. You also need to have banyan stick ready for the fire in case someone from another village drops by to drink. This is because the banyan wood smoulders for longer than the other wood available. If they drink kava, they will be given the long-lasting, smoldering banyan stick to walk home with for three main reasons.
#1 To keep the devils away. You never want to walk alone at night, if you do, you are probably nuts, and at the least, you should have some fire.
#2 To help you light the way home, so you can actually get there.
#3 To let anyone who may pass you know, you have consumed kava, so they can respectfully hush conversations to a whisper.
If you show up at a village to drink kava, and they don't have a banyan torch for you, it is considered a tabu practice, and extremely rude. If you are from a neighboring village, you have the right to get miffed.
Informally, the cicadas are known to be the "kava alarm." There are generally no lights to be had but the fire. If you do not start chewing your kava and preparing it around the time that the bugs are screeching at sunset, you might not get to prepare it before the sun sets on you, and leaves you without a head full of kava - because seeing where to spit it, and the equipment needed to squeeze/prep it will be difficult. It also times things so that the bugs shut up about the time that it gets dark, the men start drinking, and the people drop the tone of their conversations as well.
So nowadays, when I hear cicadas, the urge to have a shell, turn off artificial lights, and have everyone around me start whispering kicks in.
Everyone who loves kava should, at least once in their lives, experience chewed kava from Tanna, and stone-ground from the northern islands. (With the little coral bat.) Nothing I have had anywhere, at any time, compares with the clean buzz and intensity of the experience.
Maboos maboos!
Iahi
