Absorbed in big sister's love juice with cucumber

Wakaba-chan is the older sister in the Omugi family and the protagonist's half-sister. She recently broke up with her boyfriend and now can't help but masturbate in her room every evening. The protagonist overhears her moans every evening and lightly jerks off. However, something incredible happens... Wakaba-chan masturbated so hard that a marker cap got stuck deep in her pussy and can't be removed without outside help. The girl decides to call her half-brother...