[NSFW warning] It seems the image was deleted as I was searching, but seemed to look remarkably like a character I found while image searching.
The FMC (presumably named Claire) of this 18+ manga: シスターじゃない日のクレアさん (＂Sister ja Nai Hi no Cleaire-san - She's Not a Good Girl Tonight＂) has the same bangs and a similar face from what I remember of the image you shared.
I assume you already have the source, since the link is from the original twitter post, and this and the other piece were posted to Danbooru around the same time as your post. I can't seem to find any similar characters on Danbooru so it might be an OC or very obscure media. I don't think you'll find the source unless you can contact the artist, though. Good luck!
Tips
if a URL fails to load or returns 403 Forbidden, try entering the link manually into the location bar and hitting enter. since some sites have fairly ridiculous hot-link-protection.
link directly to an image if you can
avoid posting video links, facebooks links, private sites. i don't use Flash, or have a FB account - same probably goes for other people =P
we use a LAME filter on all anon posts. although reasonably restrictive, if it affects you, consider logging in to disable it, or write a less commercial/cheesy/offensive post!
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