There is actually some science to the idea of eating raw cannabis. Research has shown that cannabinoids available in the raw plant do in fact have the ability to stimulate cannabinoid receptors. Compounds like THCa, CBDa, CBN and others. Thus eating or juicing cannabis may in fact convey beneficial effects on humans without the high as the only when heated does THCa convert to the psychoactive form THC.
To consume cannabis raw you eat the raw leaves and buds straight from the plant or more commonly by adding them to a juice mix or smoothie with other vegetables. Starting recommendations are 15 leaves a day and one or two 3 inch buds.