[Jukujuku Juvenile (Seibee)] Well-mannered mother's indecent sex education [innyinny]

A voluptuous, doting mother turns her young son Yasuke's messy little accident into a hands-on sex education, stripping his pants off and wrapping her expert lips around him until his very first climax spills out, which she happily swallows as a demonstration. Her arousal proves impossible to contain, and she spreads her plump rear and thick thighs to teach him the real thing, even as he worries about getting her pregnant. By the end she is heavily knocked up and entrusts him to her equally busty sister Erika, whose resolve lasts all of thirty minutes before she sheepishly requests a hand job from the boy herself.