That Time in the Break Room

So last week, I was on my lunch break and hanging out with a few coworkers. We were chatting when one of them, let’s call her Sarah, who's really into flirting but always keeps things light, suddenly leans in close to me while we're talking about after-work drinks. Next thing you know, we're giggling like idiots as she whispers something naughty in my ear that sent chills down my spine. The next day at work, I couldn’t stop thinking about it, and now I’m kinda wondering if this is just normal friendly banter or if there might be more to it than I think? Has anyone else had a similar experience where they weren't sure what to make of their coworker’s signals?