I wish I could go to school wherever this is. Original post here.
Bonus Image Provenance: I commissioned Bacchus at ErosBlog to research this image further, and he has come up with the following additional details.
Your Tumblr image traces back to a Japanese-language site that’s quite unfriendly with popups and login demands, but it is here:http://www.pixiv.net/member_illust.php?mode=medium&illust_id=27187729
Google Translate renders the accompanying Kanjii (artwork name?) as “Woman’s Robocon Section”. It’s “by Sukabu” and this linked page of self-similar artworks strongly suggests to me that Sukabu is the artist’s name.
http://www.pixiv.net/member.php?id=728801
Some Googling confirms that Sukabu is an anime artist who does a lot in this style:
http://theotakukid.com/2010/07/sukabu-gallery/
http://danbooru.donmai.us/posts?tags=sukabu
http://g.e-hentai.org/g/472967/4a7cc96dab/A closely-related image to yours (same setting and characters) is here, along with more Sukabu work:
http://www.hongfire.com/cg/showphoto.php?photo=204187&title=original-sukabu-artist&cat=500
Unfortunately I was not able to find any significant English-language info about this artist.
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.