What do 자지 and 보지 literally mean?

 ANSWER: A son's (子) branch (枝)? A treasure (寶) pond (池)?

My Korean-English Dictionary defines 자지 as a pure Korean word for "penis," and 보지 as a pure Korean word for "vulva," but I have read HERE that 자지 (子枝) was originally a Sino-Korean word that literally means "a son's (子) branch (枝)," and 보지 (寶池) a Sino-Korean word that literally means "a treasure (寶) pond (池)." 

Today, Koreans consider 자지 and 보지 to be vulgar expressions, but "a son's branch" and "a treasure pond" do not sound vulgar to me.

By the way, the following is an expression that some Korean men use to describe themselves as being very busy, though they probably use it only when among close male friends:

오줌 누고 자지 털 새도 없다.

"[So busy that] there is no time to shake off one's penis after peeing." 

From Dong-A's Prime Korean-English Dictionary

From Dong-A's Prime Korean-English Dictionary