"We might have good chemistry." My childhood friend's big and hard thing is stirring up inside me, oh no... I'm gonna cum again...! Only I know the secret of the handsome and popular Makoto. He has erectile dysfunction! On that day, I was changing at Makoto's house and he got hard between his legs!? Can't be, why does he get up by me!? "Help me for a while." He said, asking me to be his sexual partner. Makoto, who keeps getting erections at home and even at work, only desires me... Just when I thought we have to stop this type of relationship, Makoto said to me "Want to try being more than just childhood friends?" 「俺たち、相性いいかもな」硬く大きくなった幼なじみのアレが私のナカをとろとろにかき混ぜて、ダメ…またイッちゃう…！イケメンでモテる真琴には、私だけが知ってる秘密がある。それはEDだということ！ある日、真琴の家で着替えていたら真琴の股間がビンビンに!?うそ、どうして私で勃ってるの!?「しばらく俺に協力して」とエッチの相手を頼まれた私。勃ちまくる真琴は家でも会社でも私だけを求めてきて…。こんな関係やめなくちゃと思った矢先、真琴から「幼なじみ以上になってみるか？」と言われて…