By T-bone 61
Very few fics ever get me blushing. This one did just that, with gusto.
By Mini Nepthys
I can wholeheartedly second the rec; it was the entry I voted for in the Lemon contest for which it was written. (It tied for fourth, amid some excellent entries.) The only thing I'd add in the rec would be to mention that the later parts have some Archer/Rin as well (it's the author's OTP), although the focus remains on Lancer and Sakura.