lol. Hyperventalating is not getting high man. Try a gravity bong. Your "bag method" may be helping you get a small amount of thc that could be left in the smoke if you didnt hold it in your lungs for very long but all your doing is re inhaling tar filled air that has already had the parts your looking for taken out via your lungs. Hyperventalating will give you a light headed feeling but as far as i can see your not doing anything positive toward increasing your level of intoxication. your simply depriving your brain of oxygen.