I heard about the cake thing too but didn't see it. Nobody seems to want to replay it.
Google tells me that Sam posted some photo of the two of them kissing w cake on their faces when he made the relationship public. Doesn't look like it had anything to do with draft day. Still weird.
EDIT: apparently there was some cake thing after. If it's how it's being described, that's freaking weird. It's a draft, not a wedding.