trixe -rix-ti'e- gismu

x1 is posterior/behind/back/in the rear of x2 which faces/in-frame-of-reference x3.

Also: x3 is the standard of orientation for x2; spine (= rixybo'u, rixybo'ukamju). See also crane, rebla, mlana, pritu, zunle.

In notes:

crane
x1 is anterior/ahead/forward/(in/on) the front of x2 which faces/in-frame-of-reference x3.
mlana
x1 is to the side of/lateral to x2 and facing x3 from point of view/in-frame-of-reference x4.
pritu
x1 is to the right/right-hand side of x2 which faces/in-frame-of-reference x3.
rebla
x1 is a/the tail/appendix [body-part] of x2; [metaphor: trailing, following portion/appendage].
zunle
x1 is to the left/left-hand side of x2 which faces/in-frame-of-reference x3.
rixybakfu
t1=b1 contains b2 wrapped with b3 to be hauled on the back of t2.
ti'ekla
k1 withdraws to k2 from origin k3=t2 via route k4 using means/vehicle k5.
ti'erbi'o
b1 gets behind t2.