well any drug that goes in needles, but thats mostly because thats one of the most painful drugs to sit on. even worse would be peruvian torch cactuses....those would be difficult to sit on. also the bufo avarious toads wouldnt sit still i'd guess and would start releasing their venom in your buttcrack if you sat on one, so that would be unpleasant and difficult to do...... this is a tricky question! all smartass answers aside, if i have pot, i usually want to smoke it. worryingly the same is true of alcohol.