Duolingual is more than just a beneficial resource for those interested in master a new language. It also has gained popularity among language lovers. However, sadly, it seems that even this beloved platform is not exempt from the controversial Rule 34 phenomenon.
Many have found that Duolingo + Rule 34 union are out there. It could come as a surprise, but evidently, there are user-generated artwork based on characters of Duolingo which adhere to the infamous guideline that states "if it exists, there is porn of it."

Lily Duolingo +18 by RougeFlair on Newgrounds