When ones finger pokes through some cheap toilet paper and you accidentally wipe one of your holes with your finger.

Accidental and unfortunate anal penetration with your own finger while wiping, usually resulting from single ply or insufficient tp.

(aka "the dreaded POKEthrough")
The unpleasant experience of your finger poking through the toilet paper whilst wiping residual fecal matter from your anus.

Causes are, but not limited to, the following;
1.Inferior toilet paper
2.Excessive/enthusiastic wiping with, or w/o
inferior toilet paper
3.Not "doubling-up" the paper prior to
wiping
4.Having a longer "middle finger" or using
it for the "dig"
5.Softer than expected feces, resistance
isn't there
6."Wetter" than expected feces, absorbed by
toilet paper~regardless of quality.
Dampened toilet paper is compromised
toilet paper~it's that simple.
7.Spicy food/itch. Causes 5&6 AND the anal
itch caused by spicy food can result in
more than one poke-through per sit-down.

While wiping your ass your finger pokes through the paper and into your Rusty Sheriffs Badge.