A very bad and ugly translation from hebrew to english.
The error is built on
similarity in the hebrew form of "swearing on", and "putting in".
The street slang often makes the speaker swear on his precious mother, as if to
promis that he
sais the truth.
In a same manner, it evolved so that when a speaker is replied, the replier puts the speakers' mother's sake on his request.
A:
Uri! I am calling you for an hour!
B: Ahhh, leave me, on your mother! I feel like shit.
or
A: Did you know that
Miki sleeps with
Michal?
B: Leave me, on your mother. Why should I care?