When it comes to keeping baby happy, a rash-free rump rates high.So at diaper-changing time, don’t go messing around with just any old goop. Cover your baby’s bottom with Rear Schmear.Made by a Portland stay-at-home mom, it’s a secret blend of soothing lanolin, bee’s wax, and olive oil that keeps the itchies and owies at bay. Plus, if all that hand washing is making your mitts a bit rough, it doubles as an unscented cream.Something you can both get behind.Available at Birth and Beyond, 600 North 36th Street, suite a, entrance on Evanston Avenue (206-547-1993 or birthandbeyond.com); online at jentealsoaps.com. Need more help with bathroom duty? Check out our other local editions.JAM Wintergrass Bluegrass & Acoustic Music Festival What: Live tunes, a music school for kids, instruments for sale, and more.Why: A little twang to chase the winter blues.When: Thurs.-Sun. Schedule online at acousticsound.org.Where: Four locations in Tacoma.SQUEALOctopus Week What: Octopus feedings and kid-friendly fun.Why: Arm yourself with activities for the midwinter break.When: Thru Sat. Schedule online at seattleaquarium.org.Where: Seattle Aquarium, 1483 Alaskan Way (206-386-4300).CELEBRATEGet Looney at MOHAI What: Cartooning workshops, face painting, and more inspired by Bugs and company.Why: You know what’s up, Doc.When: Sat., 10 a.m.-5 p.m.Where: Museum of History & Industry, 2700 24th Ave. E. (206-324-1126).