Well I have a habit of that... Flirting is a dangerous territory. Sometimes, if you think the girl is joking, (and she isn't) you miss out on an oppertunity PLUS she walks out and never goes out on a date with you cos she thinks you're frigid.
Likewise, if she IS joking and you take her up on her outburst "fuck me sideways" it could get outta hand and then the police get involved... been there!
... we males really are thick ... But as they say, acceptance is the first step towards redemption.... or something like that... Also they say "A man at first tries to get out of a woman, and then the rest of his life tries to get back in" But I'm not sure about that either anymore.
"It takes a man half his lifetime to understand women, and the other half forgetting what he has learned."