Originally just the definition for getting a relaxing "high" from smoking sheesha but has been adapted to mean getting high, drunk or super ma'fuck'n done.
Thomas: Mrs. Parr, I just wanna get sheeshed.
Kirk: Yeah man, pass that water bottle. *takes a drink* fuck, that's rough!
Mrs. Parr: Oh, you guys...
Myrfield: uhh, is Yabo drunk?
Ryley: He's straight sheeshed, man, he's fuckin maxing out.