I spent most of the evening curating content I've collected on twitter about vagal nerve stimulation.
Yes... My internet search history is full of search terms involving how butt sex can cure hiccups and the odd sexual interest of john harvey kellogg inflating people's bladders to induce vagal stimulation.
Enjoy:
https://are.na/ultimape/vagus-nerve-vagal-response-stress-breathing-pooping-and-dog-butts