Lewd Sibling Duo Ver 8.1 by Mike Meier

Overview:
LSD features two main protagonists, brother - a prominent young biologist, and his older sister - a college professor. On a quest to rid the population of a terrible infertility plague that threatens the very existence of humanity, they discover that their solution has some interesting side effects on women.
Update 8.0:

- over 120 new rendered images

- 3 animated sequences

- 1 new scene

Update 8.1:

- fixed many grammatical errors and typos, thanks to envixer