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Lucifer is a wreck before him, crying out, twisting beneath Gabriel's hands, and Michael can only stop and stare at the scene before him.
Gabriel is pumping Lucifer is quick strokes, moving his fingers as he does, and his other hand is on Lucifer's chest, tugging on nipples and pinning him back, and Michael swallows.
He thinks he wasn't meant to see this, and means to leave immediately, but Gabriel turns and looks at him, still leaving Lucifer a mess, and grins at him, predatory.
"If you want him," Gabriel says, letting go of Lucifer, "You should claim him, before I do."
Michael swallows.
"It's...we're..."
Gabriel stands and crosses the room, leaving Lucifer to writhe and moan against the sheets, and greets Michael with a bite instead of a kiss.
"Join us?" Gabriel offers, and Michael's eyes are on Lucifer as he nods.
It's not long before he has regained his footing, and not long after that Lucifer is coming in Gabriel's throat, with Michael's cock deep in Gabriel.
"Why claim him," Michael hisses into Gabriel's ear as he thrusts, punctuating his speech with bites on Gabriel's ear, neck, skin, "if I can claim you?"