Keister Egg
An umbrella term for any object smuggled within one's anus (keister).
The guard gave me a good pat-down, but didn't detect my hidden keister egg.
Keister Egg Hunt
On Easter Sunday the priest makes sure to check every alter boy for hidden eggs in their rectal cavitity.
On Easter Sunday, Father O'Brien did a "keister egg hunt" and searched every ass in the church for hidden eggs!