im american
to me a roach is weed in the end of a joint you hold with your fingers that dosent get smoked and since the smoke from the other part of the joint has to pass through the roaches weed it makes it more potent you save this little bit of weed then when you have enough roaches you put them into parent joints and smoke that then you save those roaches in another pile and put them into a grand parent joint then you continue this cycle untill you have a great great great great great great... grandparent joint and the weed is super potent and demolishes your sense of reality