I'm not familiar with caapi myself (yet), but my guess is you hold the liquid in your mouth for as long as possible, because the purpose of chewing I think is for it to be absorbed by the mucous membranes under the tongue. Someone correct me if I'm wrong. I'd guess after about thirty minutes or so there's no point holding it longer. Whether you swallow it would be down to whether you want to maximise the potential of your vine versus minimise possible nausea caused by swallowing it. This is just conjecture mind, so I apologise if it turns out to be useless. Ultimately I doubt that you need to do one or the other and it's just down to what you want out of it. Might as well swallow it eh?