The easiest way to figure out if you're getting laid tonight is to determine whether the female in question is a slut or a whore. The difference you ask?...
A whore will sleep with anyone... A bitch will sleep with anyone EXCEPT for you.
Bitch vs. Whore
Whore
Guy #1 "Dude, I shtooked this chick last night after 5 minutes at the party!"
Guy #2 "What a whore... you should get tested..."

Bitch
Guy #1 "Dude, I tried to get with this chick but she rejected my ass... Then i came back later and she was getting a train run on her by everyone!"
Guy #2 "What a bitch... Haha."
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