knitting needles, especially metal ones that you can put in the freezer. You can drag them along the skin like you might a knife or needle or you can use them int eh vagina with less worry about hurtting some one, but still carfully.

Other dirty things I can think of or have tried....
ping pong balls, detachable shower massage heads, back massagers, letter opener, funnel, turkey baster, earplugs, hairbrushes... really i am sure you could walk into any room in the house and if you tried really hard you could think of somethign dirty to do wiht most things.