I know this probably comes up alot, but what are some ways to increase the length of my screams? I can do some guttural screams like the Norma Jean, and The Acacia Strain, but not like Underoath. I also wanna learn how to do the high-pitched Underoath sceams, any ideas?

Any tips for making them more drawn out?

Check out these bands for what I wanna be able to do:
Well you can get your voice into falsetto mode, then somewhat close your throat, and sing with closed throat in falsetto mode.

Fake scream, but hell