In his "
Liber Null & Psychonaut", Peter J. Carroll writes:
Methods of achieving gnosis can be divided into two types. In the inhibitory mode, the mind is progressively silenced until only a single object of concentration remains. In the excitatory mode, the mind is raised to a very high pitch of excitement while concentration on the objective is maintained. Strong stimulation eventually elicits a reflex inhibition and paralyzes all but the most central function—the object of concentration.
There is also a table on page 23 where he lists various inhibitory (e.g. sleeplessness, fasting, sensory deprivation, concentration) and excitatory (pain, torture, dancing, drumming, right way of walking = Castaneda trance method) methods. I think the inhibitory methods are less popular because learning how to still the mind, for example, can take years while excitatory methods are, well,
exciting; working oneself up to a peak experience of whatever nature is probably easier, too. Here's a method I dreamed up recently, haven't tried in personally yet:
Place your sigil on the floor, get into the plank position (= supporting yourself on both forearms and tips of your toes only) so that the sigil is right in front of your face and close your eyes. Shortly before the inevitable muscle failure sets in and you collapse on the floor, you open your eyes wide open and deeply 'inhale' your sigil, as it were.
It's inspired by Spare's famous Death Posture (whatever that was, people are still bickering). I wouldn't use pain though, the danger is that your pain threshold may mount and that you'll need ever stronger stimuli to achieve gnosis.