(I'm not sure about the romanji.) http://book.dmm.co.jp/detail/b417abevy00417/
Rough title translation "Niece exploitation!Selfishly Pistoning In Her Body!(1)"
Roughly translated blurb: My niece "百花" is a JK (euphemism), and we live together. It's really a peaceful life...except one day I switched bodies with my niece! My niece's body is so sensitive her pussy clenches from the slightest touch on the nipples. Is she really a virgin?! And then I reluctantly go to her school and am attacked by a hentai doctor...! He licks my boobs and my pussy clenched repeatedly, and in an eyeblink my pussy sprays! Does a girl's body feel this good?! I mean...is it because I'm going to be exploited by a perverted dick?!