Never heard about this before, and seems it's maybe related to "Flashblood" where Heroin users would pass on their blood right after injecting, mainly to avoid

Never heard about this before, and seems it's maybe related to "Flashblood" where Heroin users would pass on their blood right after injecting, mainly to avoid withdrawal? From 2010: https://pmc.ncbi.nlm.nih.gov/articles/PMC4407801/ https://pmc.ncbi.nlm.nih.gov/articles/PMC4407801/ > During 2005, a new blood-sharing practice, “flashblood,” emerged among female IDUs in Dar es Salaam. Flashblood is a syringe full of blood drawn back immediately after initial injection that is passed to a companion to inject. Those practicing flashblood believe that the syringe full of about 4cm3 of such blood contains enough heroin to avoid the pains of withdrawal.