HUNTB-335 "I want to learn how to swim!" While doing 'so-ko' with my sister in her swimsuit... I ended up teaching my sister, who hates swimming class, how to swim. Unable to resist the swelling of her developing chest, I got an erection...

I decided to teach my little sister who doesn't like swimming lessons how to swim. I can't teach it well because I can't stand the bulge of my growing chest and get an erection! Then my sister who noticed me who was in a hurry with an erection said, "Tell me quickly, how can I get rid of it?" I can't stand it and want you to let me go, but my sister who pulls, "As expected, it's ...". I was in despair that this would be the end of the brother-sister relationship, but my sister who saw me for the first time in disappointment and suggested, "Well, if you just rub it...".