My sister told me she wanted to have sex so bad and she is only 11 she always humps things what should we do?

I think your sister should get some professional counselling, as her problem is more than just about sex or being horney. I'm sure her behavior is something she picked up from her surroundings. If you are her gaurdian I would strongly urge you to get professional counselling to learn specific exercises you can use to deal with the behavior in a healthy manner, without making your sister feel she has a problem.

Sex should never be seen as a bad thing, or that it is not something to enjoy, but it is important to set boundaries. She is much too young to be engaging in sexual activities. So were you at 13, however it is more important to take into account the seriousness of sexually transmitted diseases and pregnancy. If you are unable to keep her from being sexually active, at least get her the education and tools to make sound decisions about sex.

We don't need more abortions/unwanted pregnancies, or deaths from HIV/AIDS, or to have birth defects that were brought on by STDs, or young adults unable to have babies because of STDs they never knew they had, like the HPV (Human Papilloma Virus), and/or cervical cancer.

I wish you and your family the best! Take care and be safe!