I've been a black tar heroin addict since I was 15 and I'm 19 now so my advice is very accurate.I make my own cheese and also mainline it. It will hit you immediately but after about 15 to 30 minutes it will be in full effect so if you don't feel it after 5 minutes don't snort another line until its been 30 minutes bc that's how a lot of people overdose and die,I've seen it happen plenty of times. Also don't do too big of a line bc you can snort a batch of heroin that's up to 5 times more potent than the last batch you did so be careful. And if its cheese heroin the darker(browner) it is, the stronger it is. The same if you're doing monkey waters(black tar with water). I would advise to not ever do it though bc its hell getting off of it and the detox is the easy part the metal part is the worse and it will drive you completely nuts.