Chapter 2: A nice, long chapter. I can identify with InuYasha not getting much work done on his model; I've got unfinished models that I probably haven't touched in 20 years and enough unstarted ones to last me the rest of my life.
I like how Kagome seals the deal with InuYasha early on in their relationship, maybe not for the best reason (satisfying her own sexuality). I look forward to reading how their relationship develops.
I noticed a couple of minor grammatical errors. The past tense of "thrust" is still "thrust," not "thrusted." This is something I learned through a review here. The other thing is near the end, where you use "seamen" instead of "semen." This was a particularly jarring error, considering you usually spell longer, more complex words correctly.
InuYasha building a model in a fan fiction? A man after my own heart. The Internet is now complete! From what I can tell, he was working on a Gundam-like mecha of some sort.
I like to build models, too. I'm working on a bunch of Warhammer 40K Space Marines and a balsa wood "Super Solution" biplane by Dumas. Also, by looking at your profile, I read that your favorite band is Blind Guardian. I've named my latest fic after their album "A Twist in the Myth" and I've referenced two of their songs, so far, with at least two more to come. You may find it interesting to read.
Back to "The Study Group," I see many good things. Grammar and spelling are great and sentence structure is very fluid. Formatting is good, making the text easy to read. I like the AU setting and the prospect of InuYasha becoming involved in a relationship with more than one person is exciting. Thank you for writing!