Hmm......it is Definitely an Older age thing....
I can't figure out if the sphinchter looses elasticity like the skin...but imagine your bum cheeks like Bingo Wings..Claping the fanfare out.....
If you get deafer...so you cannot Hear it.......
Your smell receptors dull...so you cannot smell it....
Or you just don't give as many Fucks.............................but it Definitely seems to be an Old age thing...................