The expansive exploration of the anal cavity taken to an extent far beyond typical examination. In order to be considered an ass spelunking specific symptoms must be present. Extreme pain, euphoria, nausea, loose stool, and loss of bowel control are typical. In order to be an ass spelunker one must have partaken in at least 75% of the anal event and have documented the such thoroughly. Any accomplice in the even is referred to as the secondary spelunker.
Many times ass spelunking is used in reference to homosexual acts, however, ass spelunking can also refer to those of hetero origin.
"That butt pirate
goes ass spelunking nightly."
"Tuesday I went ass spelunking with Ashley and ruined her parents sheets. After she passed out a I gave her a superman