TIL Humans have the largest penis-to-body-mass ratio among primates & it has over 40 muscles and 4,000 nerve endings, making it highly sensitive.It has a unique "reflex" that allows it to become erect without conscious thought.

https://www.wikipedia.org
#til #todayilearned
https://www.reddit.com/r/todayilearned/comments/1g5kuko/til_humans_have_the_largest_penistobodymass_ratio/