I honestly don't remember this part well (it was a long time ago that I played it), but the "gloryhole" is the tablet at the back of the cave. As far as I recall the only obstacles in there are the slimes that charge at you when you move through the maze but if you are quick, you can get past them and they just fall down into the holes. I might be remembering wrong, but I don't recall there being a slime right in front of the tablet. Also, putting on the underwear literally just before going past the sigil means that you have less lust/corruption to worry about, so if there is a fight scene you can survive it.