His ears twitched when Izaya moaned loudly, feeling the muscles of Shizuo's throat contract around him, while the blond man pulled back again, trying not to choke and feeling deeply disappointed that swallowing wasn't possible.
His hand snuck towards the button of his pants and opened it, pulling down the zipper, because the clothes were restraining the hard flesh beneath it.
After this was done, his hand returned to stroking the part of Izaya's erection he couldn't fit inside of his mouth, and fondling his testicles, which were starting to draw up, as orgasm approached.
Shizuo inwardly grinned, deciding that he would mock the informant forever for not being able to last long, while it never registered in his mind that he was the one who would be mocked for knowing said fact to begin with, and for sucking off his worst enemy and enjoying it immensely.
Shizuo hollowed his cheeks and sucked harshly, making obscene slurping sounds, while he pulled his hand away from Izaya's crotch, letting some of the spit and precum that was dripping out from between his lips gather on two of his fingers, making sure they were slick.
Pushing his knee in between the other man's knees, which were pressed together, he made Izaya spread his legs slightly, the dark haired man being too distracted by his oncoming climax to notice.
Then, his wet fingers moved over throbbing skin away from his member, pressing playfully against his perineum, which made Izaya groan breathlessly and clench his muscles, before reaching his back entrance and circling it teasingly.
He could feel Izaya stiffen, because despite the absolutely delicious look of pleasure on his flushed face, and the desperate, raw lust in his glazed over eyes, he seemed to notice Shizuo's hand going astray.
"Shi...Shizu-chan—" Izaya whispered pitifully, as he immediately knew that he couldn't do anything to stop Shizuo from doing whatever he wanted, but pleading with his eyes anyway.
If he didn't have a say in this, Izaya at least hoped that Shizuo wouldn't cruelly hurt him in such damageable places.
Izaya saw white when both fingers pushed into him at the same time, the mere thought of something so vile and sordid, and the way Shizuo energetically sucked at him, pushing him over the edge with a throaty cry.
He cried out again, when Shizuo's fingers prodded at his prostate unintentionally, and his orgasm gained strength, as he helplessly released into his arch enemy's mouth.
Once Izaya stopped twitching and the muscles in his lower stomach ceased to contract rythmically, Shizuo pulled his mouth away, keeping his lips pressed together tightly, so none of the liquid would flow from his mouth.
Curiously, he swirled the white semen in his mouth several times, his eyes dropping closed at the divine taste, while his fingers were still within the other man, pushing into the silky, warm walls.
He tried to keep the liquid in his mouth for as long as possible, before he swallowed reluctantly and groaned.
The informant was still panting, and his knees buckled, and gave out eventually. Shizuo held on to his waist with one hand and let him slide down the wall carefully, despite the fact that he usually would have wanted Izaya to get hurt, especially if it was in a way as undignified as this.
Exhausted from orgasm, and shocked beyond smart replies.
Shizuo moved the fingers that were still within Izaya experimentally, watching him jolt in pleasure and wiggle his hips, both moving away from the touch and leaning into it.
Right then, a suspicion surfaced within Shizuo's mind, one that made him frown angrily, while rage lay heavily in his stomach, though he wasn't particularily angry at Izaya, he was just...sort of pissed.
And, distracted by painful physical desire, he reverted to acting impulsively, and therefore immediately voiced his anger.
"You've done this before, haven't you?" Shizuo said bitterly.
The discovery broke something within him he didn't even know existed, and plunged him into a deep disappointment he had no reason, or right to feel.
He felt deeply betrayed.