Side Effects May Include (слэш)

Alphas claim an omega for the duration of a single heat using bond bites, which usually fade within a couple weeks, allowing both parties to go their separate ways and move on if they so choose. That’s the usual way of things, anyway. However, Project Rebirth comes with a few unforeseen side effects on omega Steve Rogers. He can’t get drunk; he can’t be properly anesthetized; and his heats are fewer and far between. All of these are manageable, if occasionally annoying, but the largest, most-glaringly inconvenient one doesn’t come up until his first supercharged heat spent with alpha Tony Stark: permanent bond bites.
What was supposed to be a one-time thing turns into a permanent arrangement when Steve can only respond sexually to Tony, and Tony feels obligated to the omega who bears his mark.
Based on a Cap-IronMan Kinkmeme Prompt. For the Cap-IronMan Bingo 2019 Round 2 - Obtaining.