When Christina Aguilera goes on tour this summer, Chingy will be ''Right Thurr'' along with her. The St. Louis rapper, who shares the ''Dirrty'' singer's penchant for extra Rs, will open for her on the 29-city lawn tour, which starts May 13 at the White River Amphitheatre outside Seattle and winds down July 3 at the DTE Energy Music Theatre outside Detroit. (Tickets go on sale March 13.) Aguilera, who's still touring in support of her 2002 album ''Stripped,'' said in a statement that her summer shows will be ''raw, and different from anything I've done before.'' For the clothing-averse Xtina, we'd guess that ''raw'' is the key word here.