A on online post about someone's sexual intrusive thoughts. These posts are usually long and contain detailed sentences of explicit, often taboo, sexual material. Coffinposts are often posted on Tumblr but can be posted anywhere.
Girl: I keep seeing coffinposts on the nsfw tags on tumblr.
Guy: Yeah, they're pretty gross aren't they?
Guy: Yeah, they're pretty gross aren't they?
by arc777 December 25, 2021