You're the only one who gets me up ~Perfect sexual chemistry with a childhood friend

Story :  "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?"