1.Be level 150+ and breathless if your not breathless heres a code for breath reset !guysurkindacute and for flute !bossrushman !bossrush2 !bugcompensation and i forgot the other one and you also need to do final selection and then kill demon slayers untill your rank says exiled
2.Break the small, medium and large gourds (massive if you want, I guess)
3.Get a flute from codes, or by killing Yorrichi fragment which spawns in the top of the desert mountain (5% for flute to drop) edited because yuki boss no longer drops flute
4.Get a high-level demon to give you demon blood (see demon page dsba), or you can buy blood for 100 yen from the useful demon (blood giver) in the demon cave nearer to Toriyama village.
5. Drink the demon blood and spam the screen with fingers (mobile)/click the screen continuously everywhere on the screen. (both mobile and Pc players must spam everywhere on the screen)
7. repeat the process ALL THE BEST!!!
there are 4 forms of moon and i recommend doing it away from other players as they will try to kill you if they see you doing this. In the new update you can get moon breathing from daki who is located at the top of the volcano daki drops the blood and you MUST HAVE THE FLUTE if not you will turn into a demon if you do kill daki then you will not become a hybrid even if you meet all the requirements.
(disclaimer: this is *ALL* from experience)