Artist's upload: https://www.hentai-foundry.com/pictures/user/sabudenego/466204/Misc-Pic-009-Saeko-HotD/page/all

Story:

The tall cop, Masao, groaned with pleasure as he sank his cock into Saeko's mouth. His thrusts were slow and deep as he savored the feel of her pink glossy wet lips sliding over his long hard shaft, most of which already glistened with a thick coating of her drool. More than once, she had nearly taken him to the hilt, but she couldn't quite manage it. Tears brimmed in her violet eyes as he struck the back of her throat and she gurgled frantically until he withdrew, leaving her gasping for air, with drool and pre-cum trickling down her chin and joining her mouth to his cock. She had been forced to her knees, her arms bound in a painful box tie behind her back; she was totally at his mercy, unless she bit him, and the consequences for that didn't bear thinking about.

As bad as that was, she was grateful that the shorter one, Osamu, preferred to fuck her breasts; his cock was even longer than Masao's, and there was no way she could have accommodated even half of him with her mouth. Her breasts were quite large, but with his length thrust between them, they seemed smaller. She shuddered at the thought of taking either of these men's shafts between her thighs, but she knew they would inevitably demand it. They, or one of their colleagues who were lined up to await their turns with her. Several of them already had their cocks out and were stroking them slowly as they watched her service her first two men.

Outside the fortified police station, the zombies roamed mindlessly. Their screeches and howls were faintly audible even through the thick exterior walls, and made an eerie counterpoint to the soft groans and grunts inside. Occasionally, one of the zombies clawed at the windows, pressing its rotted face against the shatterproof glass and staring blindly inside. The cops were used to this, and ignored them. For Saeko, they served as a grisly reminder of why she was doing this.

There's a link to the full story on the Hentai Foundry page but it seems to have been taken down so it's seemingly lost.