Because I will always have the sense of humor of a twelve-year-old boy…
Over at Jewish Myth, Magic & Mysticism, Geoffrey Dennis writes:

So, as a former Registered Nurse, I often emphasize to my congregants that Judaism is a spiritual tradition that embraces every aspect of what it means to be human. Hence, at Kol Ami we encourage use of the b’rukhah of Asher Yetzer ha-Adam, the blessing for having a bowel movement.
This prayer, said once in the morning, covers all subsequent bodily functions for the remainder of the day. But the Shulkhan Arukh, the 16th Century digest of Jewish law by the legal and mystic genius Joseph Caro, also reveals a more complex spiritual tradition concerning defecation. In 3:3 Caro states:
If one wishes to palpate the rectum with a pebble or a piece of wood in order to open up the hole, he should do so prior to sitting but not after sitting in order to thwart sorcery.

He proceeds to bring Talmudic sources explaining how we leave our guardian angels outside while we’re doing our business, leaving us vulnerable to the forces of negativity which attempt to enter our every orifice (even that one).
Texts are provided to sufficiently enrich your BM experience well beyond Asher Yatzar – how to excuse the angels from accompanying you into the john, as well as formulas for protection. If all that isn’t enough:

Rabbah bar bar Hannah said: We used to walk behind R’ Yochanan,
And when he needed to go to the bathroom –
When he was carrying a book of Midrash he’d give it to us.
But when he was carrying tefillin, he wouldn’t give them to us.
He would say: “Since the Rabbis permit us [to take tefillin into a privy],
They will guard me [against demons]!” (Berakhot 23a-b)

Full story.