When a man slides, or hands his phone to a woman, with the create new contact screen already visible, while not saying anything as a means to procure her phone number.
It is effective because it eliminates actually having to ask for a woman's phone number. This makes the situation less awkward, while requiring less confidence to pull off.
Tom: How did u get Stacy's number, she is hot?!?!
Josh: I used the phone slide, it never fails.
The phone slide works 95% of the time everytime