Short Answer 
The term ‘beaver’ as slang for a woman’s vagina is informal and considered vulgar, deriving from the similarity between beaver fur and pubic hair. While its etymology is unclear, it has become a colloquial euphemism, despite criticism for being inappropriate. Scientifically, the vagina is a crucial part of the female reproductive system, serving multiple functions, including acting as a canal for menstruation and childbirth.
Step 1: Understanding the Slang Term
The term ‘beaver’ when referring to a woman’s vagina is considered slang that is informal and often viewed as vulgar. This usage arises from a perceived similarity between the texture of beaver fur and pubic hair. It became popular in general vernacular due to its euphemistic nature, which often seeks to soften direct references to anatomy.
Step 2: Historical Context of the Term
The etymology of the word beaver in this context is somewhat obscure, with limited documentation in mainstream etymological sources. Historically, it has been used in various contexts, and its adoption as a euphemism is likely linked to the soft and appealing nature of beaver fur. This metaphorical connection has contributed to its acceptance as slang, although it remains colloquial and often deemed inappropriate.
Step 3: Scientific Perspective on the Vagina
In a scientific lens, the vagina is a vital component of the female reproductive system, approximately 10 cm long and acts as a muscular canal. It functions as both the entrance to the reproductive tract and the exit for menstruation and childbirth. The vagina is uniquely designed to stretch during intercourse and childbirth, lined with a mucous membrane to provide protection and moisture.