[Seitokutei] A Story About Being Trained as a Slave by Your JK Childhood Friend [pixvoliv]

In a near-future world where slavery has been reintroduced, a boy finds himself collared and leashed by his own childhood friend, who enrols him in a Slave Training Course with a bright smile and zero mercy. She strips him bare, toys with him while demanding he beg and pose pitifully, and even recruits an approving older woman to cheer on his conditioning. When she unveils an extra-thick strap-on and promises to pound every lesson deep into his trembling body, his training escalates from humiliating to utterly overwhelming.