Delete don't respond. When someone sends you a text, but you delete it and don't respond to it. This can be applied to ignoring facebook wall posts, voicemails, or rejecting someone in any other way (lunch plans, date, etc.)
Boy's text: "hey u wanna get lunch later?"
Girl: deletes text, doesn't respond
Boy in person: "hey did you get my text?"
Girl: (checks phone) "oh I don't have it here, sorry!"
Girl's friend: "did you reply to his text?"
Girl with friends later: "Get that crap outta here. I DDR'd that text. Kbye to the extreme."