Director David Dobkin has a magic formula for tricking meatheads into exploring their feelings: Simply take a worn-out shtick wherein man-children learn important lessons, then pepper it with enough bare breasts, f-bombs, scatological humor and people speaking loudly to fill two hours. Dobkin has become a master of repackaging chick flicks for people who need a fart joke or 30 to help the sentimental medicine go down. As with his last big hit, Wedding Crashers, The Change-Up concerns two mismatched buddies, glued together by their shared love of tits, cheap beer and random pratfalls. Again, The Change-Up is a surprisingly funny and crass exercise that eventually deteriorates into blubbery sentimentality. 

Essentially a Frat Pack Freaky Friday, the flick takes the two bros—Ryan Reynolds' stoned-out free spirit and Jason Bateman's workaholic attorney/family man—who switch bodies after peeing in a magic fountain. They then learn the requisite lessons of manhood, which essentially boil down to "be good to your family," "value your work," "stop and smell the roses" and, of course, "only you can be the best you." The sap and clichés run rampant, but the film manages moments of sheer hilarity. Bateman, after years as the straight man, chomps into the role of a foul-mouthed slacker with horrific child-rearing skills that include letting toddlers play with light sockets. Reynolds subdues his usual over-the-top clowning into a thoughtfully boyish performance as the family man transported into a horndog male model's body. Leslie Mann, as is her habit, steals every scene as Bateman's frazzled wife, and Olivia Wilde nicely fills the role of the manic pixie dream girl who romances Reynolds.

The charm of the performers makes the generic premise forgivable but, this being a Dobkin film, there's a dramatic shift looming large. After about an hour of watching babies poop on faces and grown men behaving like 12-year-olds, we reach the standard stare-contemplatively-into-the-sunset montages that suck all the fun out of the proceedings. Apparently, man-children do have feelings. But once they're realized, feelings transform lovable oafs into overly affectionate eunuchs. R.

63 SEE IT: The Change-Up opens Friday at Cedar Hills, Clackamas, Eastport, Cinetopia, Cornelius, Oak Grove, Pioneer Place, Cinema 99, Bridgeport, City Center, Division, Evergreen, Hilltop, Lloyd Center, Movies on TV, Tigard, Wilsonville and Sandy.