onus

       onus (n.) – burden or responsibility

for your edification:  I’m no scientist, but I do receive a regular invitation to the International Gala in Celebration and Veneration of the Digestive System.  Last year’s 72^nd annual IGCVDS party was an especially poignant event as the unsung hero of the Digestive System was finally paid its due respects.  At long last, after years upon years of standing in the shadow of the rest of the digestive tract, the recipient of the Digestive System Lifetime Achievement Award was the anus!  

Finally, the long unsung efforts of the anus were appreciated!  You know, the anus pretty much carries the entire burden or responsibility of the whole digestive system.  Burden or responsibility:  that’s exactly what onus means.  See how similar onus is to anus?  Did you know that without the anus, you’d run the risk of defecating all over yourself, anytime, anyplace.  Yes.  The onus of you not pooping up your pants all the time is on your anus!  Thanks to your anus, (I assume) you are no longer in diapers.  It’s a huge responsibility for your anus to house that external sphincter of yours. It’s a huge burden for your anus to differentiate between your various rectal contents.   Have you thanked your anus lately?  Because, again, the responsibility is yours:  the onus is on you to thank your anus.

examplification - Birthmark Tony:  The churrito tacilada quesalupa extreme is freaking amazing, but about seven minutes after my last delicious bite, the onus is on my anus to keep all contents contained.

Marjorie:  Holy crap.

Birthmark Tony:  Literally.