It’s referring to a comment a drunk person would make before doing something extremely risky. They need someone to hold the beer so it isn’t spilled during what’s coming next.
{\off I think they used "hold my beer" correctly. It can be used for any weird idea, that a drunk person would actually try (usually with a stretch), regardless if they succeed or not. I don't think that "the SOAB actually pulled it off" is part of the usage.}