Tony makes a soft, satisfied sound, sucking at him, not biting but carefully applying more pressure. His free hand moves to Jesus' other nipple, pressing down on it, swirling, slow, gentle motions, and yes, he can see that start of a reaction. Now he just has to coax more of that out of him, step by step. He wants this man so badly, wants to make him happy and keep him safe and just get wrapped up in him forever, never leaving, doing torrid things that would have him undone in Tony's arms and yeah, he's definitely going to get a hard on of his own at this point, give it another five seconds, max.