ganxo -gax- gismu

x₁ is a/the anus/anal orifice/asshole/arsehole [body-part] of x₂; [metaphor: exit, waste exit].

Also asshole/ass/arsehole; (adjective:) x₁ is anal. See also zargu, kalci, mabla, rinci.

In notes:

kalci: x₁ is a/the feces/excrement/dung/shit of x₂ (animal/person); (adjective:) x₁ is fecal (matter).
mabla: x₁ is execrable/deplorable/wretched/shitty/awful/rotten/miserable/contemptible/crappy/inferior/low-quality in property x₂ by standard x₃; x₁ stinks/sucks in aspect x₂ according to x₃.
rinci: x₁ liquid/fluid drains/strains/flushes from source x₂ through drain/strainer x₃ by force x₄.
zargu: x₁ is a/the buttock(s)/arse/rear/seat [body-part] of x₂; [metaphor: rounded surface, support].
gaxlumple: p₁ is toilet paper.
selctebi: x₁ is an orifice, with lip x₂, of body x₃.
xadyca'o: x₁=c₁ is an orifice of anatomical structure [tract] x₂=c₂ in the body of organism x₃=xa2.
klo'aka: x₁ is a cloaca of x₂.