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My childhood friend's dirty secret ~ It's my fault that my plain child is too erotic ~

"I'll show you the ropes."
--Mei and Mine, a serious and simple girl, are childhood friends who live next door to each other, although they have never told anyone.
One day, Mei gets horny from watching a pornographic video and tries to masturbate for the first time, but Mine happens to see her doing it...?
"Shall I show you something that feels even better?" He squeezes her voluptuous breasts, which are usually hidden but now bigger than before, and his pussy is drenched in her love juices...!
The first time I've ever felt such pleasure, my mind and body are dominated, and the tingling in my secret parts stimulated by a man's fingertips doesn't go away afterwards.....................
Our echo-related relationship with a childhood friend is our secret.......