if you don't like it and she only humps the bear remove the bear. she may start humping other things when bear is gone, but it might stop it completely.
dogs who are spayed hump to show dominance. it looks goofy to us humans but it's not sexual to them they are using it to show bear who is top dog
redirect her attention to a different toy or something distracting. take bear away and see if she stops it or goes after another toy. whatever you do don't allow her to start doing it to you because that means she thinks her big girl self is the more dominant one in the house.
good luck. sadie humps her brother sometimes. i just clap my hands to startle her and say no humping please and we go play with toys instead. doesn't really bother me nearly as much as my hubbie. i try not to draw attention to it so it's not such a big silly ordeal. he gets all crazy and makes it a huge thing. it's not, it's just dogs.