Moira Weir would approve. Original post here, although if you go there you will be greeted with a stern message that the image “has been removed for violating one or more of Tumblr’s Community Guidelines,” which is evidence that the pornocalypse is coming for Tumblr, a large part of the reason why these images are moving over here in the first place.
Sourced to Octoporn (indeed!) via kennyisaliveinourhearts.
Bonus Image Provenance: I commissioned Bacchus at ErosBlog to research this image further, and he has come up with the following additional details.
This image has “Pinky” for a visible artist’s signature in the lower left. A bit of searching turned up this small gallery of Pinky artwork on ImageFap:
http://www.imagefap.com/pictures/2621736/pinky-art
Pinky has a profile on Hentai Foundry with a total of nine artworks shared there:
http://www.hentai-foundry.com/pictures/user/Pinky
Your image is titled simply “Tentacles”:
http://www.hentai-foundry.com/pictures/user/Pinky/78607/Tentacles
A slightly larger version (532×800, probably just resized upward given the lower resolution at Hentai Foundry) can be found here:
Bacchus is actively taking image research commissions, and if you have adult imagery you’re curious to learn more about, I encourage you to visit Bacchus’s introductory post for his image-searching service, where you can find details about how to commission him.