Depends on the MoA -
Eat it - um, you can't get high this way..
Snort it - a heroin virgin will feel the high in full effect for about 2-3 hours, with after effects lasting a few more hours..
Smoke it - you will be sober in only a few hours.. this is not a good way to take heroin, as you trade the high for a quick rush that isn't even as good as injection..
IV it - the best of both worlds! Rush like a mo-fo (I believe thats short for mother fucker, but it would seem like mo-fu would be more logical..) for, well, thats not important - it feels like eternity, yet it's never long enough.. overall you get a good few hours out of it..
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PAK CHOOIE UNF! Do not trust the pusher robot, he is malfunctioning, we are here to protect you..