I never really did flirting much in the past, so this experience comes off as bizarre to me. It's like a flirty statement that turns into an interpreted insult midway through and then I have no idea what happened.

Essentially, girl and I went out. Girl told me 'I'm not wearing any underwear'. I gave her a grin (the best I could manage, I was totally unprepared) and whispered 'show me'. Her expression went from airy to stonefaced/genuine horrified and she went 'wtf we're in public'.

I am absolutely confused. What just happened, it felt like a flirt that turned into a shit test before I could blink. I totally don't get it, I don't even know what she was testing for. I've gone through the sidebar but I don't recognize anything that sounds remotely like this.