Yu and I are best friends who can accept each other's true feelings and talk about anything. We have a relaxed relationship where we can say whatever is on our minds without holding back. Then one day, a single comment from Yu became the catalyst for us crossing the line. "Hey, do you want to see my tits? Wouldn't it be great if we were friends who also have sex?" A physical relationship as just friends—neither lovers nor fuck buddies. "Whoa... damn... your cock was this big? This feels way too good... lol." Having sex with my best friend while keeping our usual vibe... it's strange, but it's a pleasure I've never felt before. Yu's incredibly erotic cowgirl position with her massive boobs... the way she looks up at me while giving me a blowjob. "We're still friends from now on, okay?" This is the story of how my relationship with my busty best friend changed through sex.