Shuch up! is a phrase used (accidentally) by H2O Delirious and fans.
Delirious' Word Mix Up
(BOLD is for corrections.)
Delirious sometimes gets mixed up with his words. Like "Quit blocking the car blosh!" (Correction: "Quit blocking the car wash!") or "Blow me!" (Correction #2: "Blow me up!") and now is another mixed up word: "Shuch up!" instead of "Shut up!"
This happened in the video: GTA 5 Next Gen Funny Moments Ep. 57 (Secret Club Glitch) Shuch up!
It happened when Delirious was placing C4s on a wall in the Secret Club; Lui asks him if he wants to be part of a record label, then Delirious responds with "Would you like to Shuch up?"