[YU] My Precocious Little-Sister (COMIC LO 2022-03) {Mistvern + Bigk40k}

When Mana cheerfully announces her very first boyfriend, her chubby big brother spirals into jealous panic—until an innocent shared bath after her date turns into something far steamier than either of them planned. Flushed and dripping wet, the precocious little sister catches sight of his arousal and shyly offers to 'take care of it,' escalating from an earnest blowjob to her brother tongue-deep between her thighs while she squeals protests that fool no one. Jealousy melts into sin as the two keep going until morning, ending on a comedic beat where Mana invites him to sleep together—only for poor onii-chan to get kicked out of the house come Sunday.