Not to be confused with the abnormalities in looks/faculties that can occur from being born too late in your mother's life, this term refers to an equally-unpleasant degradation of one's physical/mental health due to repeated "dashed hopes" incidents that you've encountered when needing to "answer Mother Nature's call on line 2" but no restroom was immediately available --- after having "held it" for a considerable time, you eventually see what you initially assume will be an opportunity to finally relieve yourself, and so you partially relax your painfully-fatigued internal muscles in preparation for said dump. But then at the last minute, you discover to your extreme dismay that said lavatory is in fact **not** available for you to use, either because there is already someone in there or it is out of order; you are now obliged to frantically "clinch yourself up tight" again and either wait even longer or rush off to look for another toilet. But of course it is now much harder to "hold it in" because you have unwittingly allowed your poop-load to partially "slide downwards", and so you may now encounter more difficulty in "keeping your grip on it" than if you'd waited to see for certain if you could indeed go potty before partially "letting go".
Another possible contributing factor to letdown's syndrome, of course, is if you sometimes "relax too far" when thinking that you're gonna have a chance to poop but then are not able to and therefore hafta "clamp up" again --- if you've inadvertently allowed your poop-log to "progress outwards" too far, you pose the risk of "pinching one off" when you hastily re-tighten your sphincter-muscles, and thus you may actually squeeze some of your unmentionables out in your feverish efforts to "re-establish your grip" on said yuckies. Further comments/explanation unnecessary.
by QuacksO February 2, 2020