This is merely playful dominance, not really oversexualization. Many small dogs exhibit an ego or dominance complex; they meet a new dog or person and immediately try to establish that they, though little, can hump like no tomorrow, aka they are top dog and important. It's an attention seeking issue that may not be resolved easily. The best thing to do to end it is to establish your dominance (not by humping... :) When you play with her, win. When you wrestle, hold her on her back for a few seconds. Most normally adjusted dogs will struggle for a few seconds, then submit, but my bet is she'll squirm till she gets rug burn. It will take time, but you can gradually build her respect for you.
I've been told that it's not a sexual thing. She's trying to be "the boss" She wants to be the top dog and your part of her dog family. I'm sorry I don't have an answer on how to get her to stop doing it. I would put up the stuffed animals and correct her when she does it to you and your family. Maybe you can distract her with a chewy treat. Make sure you give her a treat before she does this and not after. You don't want her to think your rewarding her for her behavior. Best of luck...this is a tough one.
It has to do with dominance, stress and libido... If she's not spayed, doing so will help.
It may be difficult, but the way to stop her is simply not to let her do it... AT ALL. Push her back, firmly, calmly and authoritatively say no, and ignore her, turn your back on her or stand up for a min. If you have to. It may take 20 times a day for 20 days, but she'll eventually give up. When she comes back and doesn't mount your arm, reward her with a chest scratch, belly rub or massage. If you let her do it sometimes, she won't understand which times she can get away with it and which times she can't, so no matter how cute she is you have to be consistent.
Dominance. She is showing you she is the pack leader. You have to turn the tables and regain control of the pack if you want her to stop. It is not sexual shes in charge.
Maybe it a personal prom
They get horny gest like female do