You wake up and the memory arrives in installments. The cocktail hour, fine. The toasts, mostly fine. Then the gaps start, and the fragments that fill them are not good: you on the dance floor doing something with your jacket, you talking very close to the groom's mother, a plate, someone's hand on your shoulder steering you toward a car. It was your friend's wedding. The most photographed, most remembered, most expensive day of their life, and somewhere in the footage is you.
First, triage the actual size of the thing, because shame is a terrible measurer. At almost every wedding, someone drinks too much; open bars are a design choice with known outcomes, and a guest who got sloppy on the dance floor and was poured into a cab is, at most weddings, a Tuesday. If your fragments amount to embarrassing yourself, loud, sloppy, sentimental, gone by ten, the apology is real but light. If your fragments involve damage, a scene, a confrontation, an interrupted moment, something broken, a toast that wounded someone, the apology is a different instrument entirely. Figure out honestly which one you owe, and if the gaps are too big to know, part of the apology is asking.
For the embarrassing-but-harmless tier, send it today, keep it short, and let it stand upright:
Well. I owe you an apology for my performance last night. The open bar and I made some decisions, and I'm sorry if I was a mess at any point during your day. I hope it stayed background noise, but if it didn't, tell me straight. None of it touches how happy I am for you two, it was a beautiful wedding and I'm lucky I was there.
Notice the mechanics. It names the thing without a forensic reenactment, invites correction in case it was worse than you remember, and doesn't grovel, because a groveling apology makes the hurt party manage your collapse, and a newlywed on honeymoon morning has better jobs.
For the caused-actual-harm tier, the shape changes in three ways. It goes to the right people, which may be more than the couple; if you said something to the groom's mother, she gets her own message, not a relayed sorry. It skips the comic register entirely, no "the open bar and I," because charm in a real apology reads as an escape attempt. And it names the act, owns it without the alcohol as defense, drinking explains, it doesn't excuse, and asks what repair looks like:
I've pieced together enough of Saturday to know I owe you a serious apology. Interrupting the toasts was wrong, and it took something from a moment that mattered to you, at your own wedding, and I hate that it came from me. I'm not going to hide behind having been drunk. If there's anything that would help make it right, including apologizing to anyone else affected, I want to do it. And if you need distance from me for a while, I understand that too.
Two timing rules, both counterintuitive. Send it fast, today, not after the honeymoon; silence reads as either obliviousness or hiding, and the couple's version of events is currently being set in group chats you're not in. But expect the reply slowly and demand nothing; "no response needed, enjoy the honeymoon" is a kindness that costs you the reassurance you're craving, which is exactly why it works.
And the mistake that outranks all wording mistakes: the minimizing follow-up. "Haha was I a disaster last night?" sent to the group chat, fishing for "you were fine!", is the anti-apology, it recruits witnesses to shrink the thing before the couple has spoken. If it was small, your clean apology lets everyone file it as small. If it wasn't, the joke version tells them you don't know the difference, and that's the reputation that outlives the hangover.
One apology, right size, right day, standing on its feet. Then let the couple, and time, do the filing.