For this particular example let's just focus on one body part: Mouth, Lips, Tongue.

Long story short, I commented on this chicks job position, that she was like a bouncer with a list to an exclusive VIP club, yadda yadda. She couldn't really look at me directly because she was busy checking said list, but as I watched her for a moment I saw her tounge swirling around her mouth, lips closed.

Could this perhaps be a variation of an IOI?

Because of her position she can't necessarily directly flirt with me because technically I am a client of the place where she volunteers/works.