Write a tongue twister and try others given by others?

The hardest tongue-twister is reputed to be:

"The sixth sick Sheik's sixth sheep is sick"

Well it wasn't necessarily a tongue twister...but in Cosmetology, there's a hair cut called "blunt cut" which is all one length...saying "blunt cut" a million times though makes you wanna pronounce "cut" with an "n" to rhyme with "blunt." It's kinda embarrassing ;D

From an old Reader's Digest (somewhat surprisingly).

Three grey geese in the green grass grazing.

Grey were the geese and green was the grazing.

And one I just found on the internet

Sister Shelly says she shall sew sheets

And another I remember:

The big black bug bled black blood.

She sells sea shells by the sea shore