when i got a good amount of weed to smoke i hold it for like 3-5 seconds i guess. but if all i got is a roach i usually hold the smoke as long as i can. after doing that a while sometimes now after i do that my head throbs for a minute i've always known its from the lack of oxygen but i figured maybe holding it longer gives your red blood cells or w/e more time to transport the shit through your body, but i guess i'm just stupid and now i know why. from all those brain cells i been killing doing that shit :thumbsup: