Not Sheela na gig related but should prove a fascinating read

Well known expert in Japanese Studies Dr Stephen Turnbull, has released a new book called  Japan’s Sexual Gods Shrines, Roles and Rituals of Procreation and Protection.

Japanese shrines have many deities represented by phalluses and female sexual objects. This book provides a gallery of photographs and locations along with details of their rituals, festivals.

http://www.brill.com/products/book/japans-sexual-gods

There is also a YouTube channel which has a number of videos relating to the book

https://www.youtube.com/channel/UCiknUIkagXP9IN_ftqSil_A

The book on Amazon

http://www.amazon.co.uk/Japan-Sexual-Gods-Procreation-Protection/dp/9004288910