It started sexy and became very creepy very fast.
This. I think Allison is an attractive lady but the purpose here was probably to make it awkward. I imagine she is giving these types of dances to NBC execs.
As with everything on that show, that scene was meta as hell. Even McHale had to state at the end for those viewers (and GIF makers) who didn't get it that it was taking Annie's sexualisation just a bit too far.
Yeah, it got ridiculous about halfway through but that was the entire point. It started out as the kind of overt (and awesome) 'erotic Annie moment', but it just got silly about halfway through.