Few things are more attractive than a flirt who is confident, playful and clever. The next time you hit it off with a classmate, coworker or friend-of-a-friend, slip him the digits in a slick, sneaky way. You'll amuse and intrigue him as he realizes what you're up to.
Get your hands on his phone and save your contact info to it. The trick is to get him to give it to you -- snatching it up without him knowing is an invasion of privacy and is likely to irritate or offend him more than anything else. Coax him into showing you a picture or song, and hold your hand out as you ask for a closer look or listen. Work a bet or fascinating fact into the conversation, and nonchalantly say, "Here, let me see your phone, I'll show you," and dial or save your own number just before pulling up Internet search results. As you leave, tell him to give you a call sometime, and let him discover that you did, in fact, give him your number.
Persuade him to hand something to you, and slip your number to him as you hand that item back. This works especially well when you're at a party, bar, restaurant or other social gathering where the two of you will both be for a while. Excuse yourself for a minute and jot your number down on a small piece of paper. When you return to the conversation, continue chatting as normal, and after a few minutes ask him to pass you a snack bowl, flyer, book -- whatever is nearby, and that you can casually hold onto as you finish your conversation. As you get ready to leave, reiterate how nice it was to chat with him, and hand him the item -- along with your number -- as you say goodbye.
Pretend that he dropped something and attempt to hand it back to him. This is especially fun when you bump into someone you recognize but don't know. Approach him from behind with a folded paper that says "Call me, cutie" or something similar, and contains your name and number. Say "Hey, you dropped this," and hand off the paper as you walk past him. Turn around, wink, and keep right on going.