You have to feel a little bad for Christina Aguilera — between the American Idol rumors (Mariah! Nicki! Kanye?) and the Britney of it all over on X Factor, it’s been easy to forget that there is another late-nineties diva currently dishing it out on a nationally televised singing competition. If reality shows were lunch tables, Christina Aguilera would be stuck over next to the sexually active band geeks, while Mariah and Britney were kicking it Plastics-style. (That metaphor is based on status, not ratings, because this is high school. That’s how things work.) But Christina Aguilera is still here, and as we have learned from her interactions with Adam Levine, she will not go down without a fight. So here is “Your Body,†the first single off her conveniently timed new album, Lotus. It is about sex. Are you paying attention now? Cool, that was the plan.