Jibbali

šeff - to fart silently (JL 260)

with metathesis

PS
*pšw - to break wind silently (SED I No. 57ᵥ; Kogan 2011: 231)
Level? Akk. pašû ‘leise furzen’ (AHw. 846) appear to be non-existent (CAD P 267).