Starker Smut Prompt: Established relationship, 'confession' play.
Peter 'confesses' his feelings--physical and emotional--to Tony while sitting in Tony’s lap (reverse cowboy), and Tony touches him, gently teases him about what he 'reveals'.
Overall, it’s an affectionate scene. There are notes of humiliation/embarrassment, but they’re in a safe environment--Tony’s bedroom, or maybe a shared bedroom (if they’re in an established relationship). Lights down low, door closed.
Peter is nervous, but excited and trusting--he's the one who suggested it, and he's thrilled Tony agreed to it.
Tony is proud of Peter for asking for what he wants. He enjoys the fluster in Peter’s expression and body language, the red-pink stain of Peter's cheeks and the tops of his ears, the warmth of Peter’s skin. He loves the way Peter keeps struggling, aroused and breathless, to get the words out, how his gorgeous boy keeps shifting and fighting with himself to keep from pressing down more insistently into Tony’s lap.
It’s not about religion--it wouldn't be, not with these two--but Peter's words and Tony's acceptance of those words carry a kind of reverence, of sanctity.
They are together, they are safe, and they want each other. At this moment, nothing exists but them.