
do assholes actually twitch?

No idea. Tried to google that but a bunch of diseases and cancer pertaining to the rectum/anus popped up...... and a certain passage as well.
The passages goes:
“If the anus, that some also call ‘ring’, twitches, it shows inspections, abuses, and the discovery of secret matters”
Hmmmm secret matters
Maybe gay porn will help lolol

To answer your question, YES. you have what you call an 'external anal sphincter' which does the twitching. During rectal exams for neurologic disorders, doctors asks their patient to squeeze while they insert a lubricated and gloved finger, a tightening on the examining finger means you have a positive 'anal wink' test. This test is most commonly used to determine if you have damage on your spine (positive anal wink test means normal), specifically your S4 and S5 spinal segments.
and I'm in love with it all over again. so pure and wholesome. I love Kazuma and Chiaki's relationship, can't believe they've been together for at least 10 or 11 years and still as much in love with each other as in the start. True love <3 they're great dads and I love their family bond with Ayu