My boyfriend — I mean actor Channing Tatum — appeared on “The Ellen DeGeneres” show this week to promote his latest movie, “Dear John,” which managed to knock “Avatar” out of the box-office top spot this past weekend. Of course, Ellen brought up Tatum’s former career as a male stripper — watch the video to see the proof — and cajoled the actor into giving her a little demo. Sadly, Tatum could only work up the energy to squat over Ellen’s lap and pop his booty a few times. Ellen’s right. A few dollar bills might have prompted a more enthusiastic showing.