I've seen people recommending a Box-o'-Death for that: buy a brick of D6, put them two-per-slot in a compartmentalized box (like a tackle box for fishing), close the lid, shake, then open the lid again. Personally, I've had good success with those
really tiny d6's (Google "5mm d6", or maybe even 8mm) inside a clear pill organizer.
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One of these babies is still reasonably compact and sturdy and will roll you cluster hits for days, and you don't even have to open the lid (although you may have to squint a bit, make sure you have very easily readable dice). And if a normie asks why do you have dice inside a pill box, you tell them you have a gambling addiction these are your daily meds.