The word "Gnosis" stems from the Greek word for knowledge, γνώσις. It is defined as the knowledge of the heart or insight about the spiritual nature of the cosmos. In Chaos Magick it refers to the altered state of awareness in which the will becomes magickally effective.
It is similar to the Buddhist state of Samadhi which was made popular in the Western world by Aleister Crowley.
Gnosis is achieved when your mind is focused on one singular point, be it thought or goal. In this singularity no other thought may reside, only the intent of the magician. At the culmination of gnosis, the intent is send deep into the sub-consciousness and forgotten. There the magickal seed is planted, takes root and comes to fruitition. Spare referred to it as death posture.
Usually we are thinking feelings, we label whatever we feel, be it anger, jealousy, sympathy, happiness etc. To reach gnosis through emotion you may not think about what you are feeling but experience it completely. Don't attempt comprehension, just feel.
In this exercise you are focused on the singularity that is the present. For this all thoughts must perish as thoughts mean that you dwell on either past memories or the future.
For this exercise lie down comfortably and relax. Use one of the breathing exercises to calm your mind.
Feel into your body, don't project thoughts but just feel. Start with your toes, if you find it hard to do move it slightly. Move up the legs slowly to the knees, stomach, breast.
Do not analyse, do not evaluate what you are feeling, just feel. Experience your body and let the mind fall silent. This silence will stop once you decide whether or not you like this feeling. Only thoughts are capable of deciding on likes and dislikes by comparing what you feel with past experiences.
Try to intensify the feeling, don't move away from what you experience but dive deeper and deeper into it until you reach the ecstatic singularity.
This heightened state is then used to charge the sigil.