Is it true that you've freestyled for over 5 hours straight before?
Absolutely! In order to be as fluid with rhyme as I saw in my vision of who I would become, I had to have this flawless skill. The best and in my opinion, ONLY way to develop this is practice. How can you blend practice and income at the same time? put yourself in the position to be rewarded, I guess as I got better at working the crowd (a skill I had pre developed before music) my crowds would grow and I'd get to watch as a third person like from a higher being, as Ellevan was rapping, I just got to watch and study.
So yes, I'd get lost in this position and just sit back and enjoy. As long as you hydrate well enough. It's the best mental work out one could do. Freestyle rap for over an hour straight. Try it!