親同士の再婚でボクに超可愛い義理の妹が出来た。その妹というのが、かなり内気で気弱な娘なんです。はっきり嫌だと言えないのをいいことにチクハラ三昧！最初は服の上からポッチをツンツン、それから毎日毎日乳首をしつこく触っていたら、ヨダレを垂らすぐらいに感じまくって、乳首だけで何度もイッてしまうぐらいの変態女子に変身！最終的には自分から「お兄ちゃんに乳首を触って欲しい」とちゃんと自分の意見を言えるようなしっかりした女子○生に成長しました！

My parents remarried, and I gained a super cute stepsister. This stepsister is quite shy and timid. Taking advantage of the fact that she can't clearly say no, I indulged in all sorts of nipple harassment! At first, I would poke her nipples through her clothes, and then I persistently touched them day after day until she became so aroused that she was drooling, and transformed into a perverted girl who could orgasm multiple times just from nipple stimulation! In the end, she grew into a strong-willed high school girl who could properly express her own opinion, saying, "I want you to touch my nipples, big brother!"