"Back here!"
Riku was lured into the alley as much by Kairi's half-stifled laugh as by Sora's hiss. He turned the corner and let himself be yanked against the brick wall. He was prepared for it, only feigning a gasp of surprise - but even knowing it was coming, Sora's kiss could not be prepared for. Riku gasped again, less an intake of oxygen than an intake of light.
"Hey, you're hogging him!" Kairi whispered, unable to keep a giggle from her voice. Sora grinned an apology at her and stepped aside, and their girlfriend sidled in and kissed Riku too. Kairi tasted like starlight, tingling-cool and sweet, a bracing contrast to Sora's sunny tangerine. Riku slung his arms over their shoulders, but didn't pull them - they did that themselves, snuggling up and jockeying for position until their limbs and laughter were all a-tangle. Grinning, Riku kissed Sora again, adding that little bite to his lower lip that never failed to make the other boy's hand clench in his shirt. Sora closed his fingers right on cue, but then retaliated with a swift hand down the front of Riku's pants.
Things went a little blurry after that: Riku lost his shirt, Sora his pants, and who knew where Kairi's underwear had gotten off to. Riku had two fingers inside her under her skirt and she was gyrating slowly against his hand, but both of them only had eyes for Sora when he shoved his boxers down to his knees and proceeded, with enthusiasm and not a trace of shame, to stroke himself hard.
Riku never stopped caressing Kairi, but even her soft moans couldn't tear his eyes away as Sora gripped his shaft and teased the head gently with his fingertips. Riku could almost feel the friction from his calluses with every motion, groaned when Sora tipped his head back and closed his eyes. Kairi nuzzled his jaw in commisseration, then turned her face to his shoulder with a stifled whine. "I got you, it's okay," Riku whispered as she shuddered hard against his hand.
"Uh, Riku..."
Riku tensed at Sora's dismayed tone. He glanced up, then followed the other boy's gaze upward... "Is that Merlin?" he muttered.
"Oh god," Kairi moaned into Riku's shoulder.
"Shh," Riku whispered. "I don't think he can see us. Just keep it down."
"I can't," Kairi confessed, writhing as her body started on its second orgasm.
"Damn," Riku hissed. "Here." He offered his wrist, and Kairi bit down on it as Sora came forward to embrace them both, further muffling their cries.
Presently Kairi spent herself and let go Riku's wrist, leaving him two red half-circles to admire. "Is he gone yet?" she panted.
Sora glanced up. "Yeah, he's gone. Sorry, Kairi."
Kairi shook her head with a smile, tilting her head against Riku's shoulder. "S'okay. You know we have to get our revenge, though," she added with a devious grin at Riku.
Riku smirked back, and pounced.