She began to masturbate

After coming in, Jazz locked the door from inside. Then she began to undress.

In their childhood, Danny and Jazz used to take a bath together, but it's so far that he couldn't remember anything. Jazz used hid her body under school uniform or lab coat, but her gorgeous breasts and ass still made a lot of guys go crazy. However, it's nothing compared to the voluptuous, naked body Danny was seeing. Her skin was smoother than the best kind of silk, her curves were like a statue with a perfect golden scale.

The next scene shocked Danny even more.

Jazz glided her middle finger over her labia and began fingering herself. She rubbed up and down her wet cunt, stroking her clit, circling around her fuck hole, rubbing the wetness all over her labia and pussy hair. From Danny's point of view, he saw her cunt spread open, and she spread her pussy lips wide revealing her pink twat. Her moaning got louder and louder; Danny used to think that Jazz installed sound-proof wallpaper inside her room to hide explosion sound from her experiments, but now he discovered the truth.

Jazz quickly reached climax. She let out a very loud moan, then collapsed to the bed, the fluid squirted from her pussy. She began to murmur in a low tone which couldn't be heard if Danny didn't have superhuman senses:

"Why... why didn't you accept my love?"

Seeing all these scenes, Danny felt extremely aroused. The thing in his pants slowly rose.

No, this is wrong... She's my sister... I must think of something else... Haha, if boys in my school know this, I wonder how many will collapse due to heartbreak... Should I tell Tucker... No, it's too cruel...

Then he became curious: I never saw any boy who can win Jazz's affection, even a bit. Who can steal her heart?