Sentence:  I hit the flush button and I feel the air from the VCHT (vacuum, collection, and holding tank) system pass over my <WSD>grundle</WSD>. That one full second of cool air down below is one of the few perks of the day and of the job. 
Meaning of the word marked with <WSD> tags:  The perineum; the area between the anus and genitals.