[Nekonomori Maririn] Boy's Felings♡ (COMIC Muga 2004-11) [Decensored]

Two curious schoolgirls in sailor uniforms stumble into a strange little experiment, wondering aloud what it would actually feel like to hold back pee the way a boy supposedly does before cumming, with one musing that "the feeling when a boy cums" might be something they can experience for themselves. What begins as innocent bathroom talk quickly turns into a wet, trembling first attempt with a toy, the girls gasping and shivering as streams spray and bodies squirm in breathless discovery. The story closes with flushed cheeks, satisfied sighs, and a lingering question about whether they can now understand what a boy feels when he finally lets go.