[Harumachi Tsurara (Shichoson)] Devil's Proof [Suikashoujo]

Yuna's tearful vows of fidelity mean nothing to her jealous girlfriend, who binds the trembling schoolgirl in rope restraints rigged with a hidden stun gun and demands she prove her devotion through pain. Shaped by a family destroyed by mutual betrayal, the lover's obsession with a flawless romance turns the interrogation into bdsm torment—shocks wracking Yuna's bound body even as whispered promises of cunnilingus and sex toys blur the line between punishment and pleasure. A dark, possessive tale where the birdcage motif says it all: some loves are beautiful cages you never escape.