Onee-san's Premature Ejaculation Conquest Plan!

Sho seeks advice from Hebinuma after ejaculating immediately during first sex with girlfriend Amamiya and failing to continue intimacy. Hebinuma inspects his penis, he cums at once, and she fits a cock ring and orders a week of endurance training at her house without removing it. After repeated oral, manual and bondage stimulation, on the final day they begin penetrative sex when Amamiya arrives. Hebinuma reveals she wanted both as her own and had already trained Amamiya, then leads a threesome. Sho continues penetration, kissing and oral with Hebinuma; the story ends with Hebinuma in bondage gear dominating both with feet and restraints.