This is called the reject me opener. It was developed by style and it works amazingly.
Basically go up to a girl and say
Hey can you reject me please with the most serious face you can do. and just go from there you can either walk away and go to another girl or you can try to develope a routine out of it all

beautiful... simply amazing...

Do not underestimate how hard it is to get a girl to shoot you down when you want her to!

Honestly, this is what I use when my mojo isn't exactly kickin' and I need a warmup set or two and, if your eye contact and body language are at all ok, most girls will say something like "but we don't want to get rid of you" or "why should we shoot you down" and you are already in set--so make sure that they are at least cute!

If a girl is indifferent, it is usually a test, so, if she comes up with something like a weak attempt to shoot you down, neg her by asking her friend "man, that sucked, does she like never get hit on or why can't she do a decent job of telling me to fuck off?"

I've had women screaming at me to fuck off and I'm just standing there with her friends, laughing and coaching her to yell louder and be mean, make me feel it!

Great fun, a great opener and it really makes you see how stupid it is to have approach anxiety.