When punk was new and Iggy Pop was already an icon, it was reasonable to explain away his teenage antics as his birthright. Even when Pop got well into his 30s, teen lust seemed like something of a progression for someone who at 21 wished he was a dog. But now that Pop’s into middle age and singing about junior-high snatch (see “Pussy Walk” from his latest, naughty little doggie), I can only think that a good shrink would do the guy some good. And if it would end up dimming the raw power of his live shows, so be it. Psychotica opens at 7 p.m. at the Capitol Ballroom, 1015 Half St. SE. $20. (202) 554-1500.CP