I have have a go to for when the conversation begins to taper off. If there is a silence that last more than five or six seconds I'll just say happy birthday. Then of course sge says it isn't her birthday at which point you puppy dog that shit and say : " But it will be ;)
Next time your there cut in the line to assert your dominance over the betas, and then cool as a cucumber just whip your dick out and slam it onto the counter, trust me you'll find out if she likes you.