This was an image from Tumblr several years ago, but it looks like it doesn't exist there or anywhere else anymore. Only instance of it I can find is https://archived.moe/r/thread/18154896/ where someone else is asking where it's from and no one replied

It looks like it's probably from a doujin, but I don't even know what the ship would be. This mystery has been haunting me for months now, literally posting to 4chan for the first time in hopes of an answer. Anyone got any clues?

The file name of the Tumblr image was tumblr_ntb3yr8nLG1t0oz8yo1_1280