Meaning
What does Cumbrain mean?
A cumbrain is someone, who is so focused on adult entertainment in life, that he only sees the sexuality of every situation, and every place he comes across, he thinks of how it would look like in an adult entertainment.
The joke gained greater interest in the May of 2019 on 4chan, where these kinds of dudes are plenty, so many users may have felt a bit of relatability.
Origin
What's the origin of Cumbrain?
Cumbrain as a term for someone, who is addicted to this content first appeared in the /co/ thread of 4chan, but it was still unrecognized for seven years.
It gained proper prominence in 2019, when a user created a depiction of the adult entertainment addict, with spit dripping from his perverted mouth, while he is struggling to solve a kid’s puzzle.
Spread & Usage
How did Cumbrain spread?
Since it had gotten a depiction, it had been spreading all over the message board, appearing in several different threads, and referred to in several of the conversations on the site.
The incel community present on 4chan makes sure, that the meme stays relevant, as it is acting like a direct message to them.

External resources
- Know Your Meme – Cumbrain