If she’s not interested in dating you but she wants a free meal and she puts out because she thinks that’s her end of the bargain, it’s whoring. If she isn’t interested in dating you, but she puts out because she wants a one night stand and/or is super horny, it’s slutty. If she is interested in dating you and the chemistry is really good so she puts out on the first date because you’re both having a great time, it still leans towards slutty but it’s not always as much of a red flag as the other two scenarios.