Understaning English

[Unregistered here]

I am reading a book. I do not understand what these exactly means.

1. She's just standing around looking like she swalloed a live fly.

2. I saw his eyes flicker and then he smiled a sideways twitch as if he was sharing a secret joke with her.

Please translate these into simpler English. Thank you.

[Tdol]

1- looks uncomfortable
2- his eyes showed some reponse and he gave a slight smile which only she was supposed to see or understand