Kieren's mouth goes slack once more, a delicious little cry pushing past his throat and Sirius can't help but grin through his own pleasure. He slides one hand down again, feeling Kieren's soft hair against his fingertips, his back bowing as, with the other, he pinches one nipple between thumb and forefinger.

It sends a jolt straight down his spine, his cock jerking between Kieren's lips, and his legs shaking. "Shall I-- shall I warn you?" he asks, barely capable of stringing words together at all.