From PITB:
Xtina Aguilera welcomed a very special guest on stage at her recent Back 2 Basics tour stop in Philadelphia, PA during her performance of the song Nasty Naughty Boy. Apparently each night she picks a random guy out of the crowd and brings him on stage for a whippin' ... in Philly, she selected David Arquette:
lol, wonder what courtney said, cause i think i can see a little boner on mr. arquette!