Yo friends are trippin. I never hold it in for that long. Just get smoke from the joint or blunt and then suck it in for how ever long you want to. Personally I dont hold my breath, I just breath regularly after this or if I'm talking I'll continue talking and the smoke will come out graduately while doing this and there you go. Theres no need to hold that smoke in your system for fuckin 30 seconds rofl.