My sister, who attends a sex-crazed all-girls school and has enormous breasts, asked me to teach her how to put on a condom because she wants to 'graduate' from 'raw'. She said, 'I want to practice, so let me make you hard,' and started jerking me off. Facing my sister like this, forbidden erection! As she practiced putting on the condom, touching my cock more and more, it got harder and harder. My sister unexpectedly became aroused seeing it. Unable to hold back from just sucking, she squeezed me with rapid, high-speed raw thrusts, and I ended up ejaculating inside her three times in a row without pulling out.
