Humping ..

Has anyone’s toddlers been humping things? I don’t know how to handle it. I definitely don’t know where she learnt it. I’m her primary carer she doesn’t go to day care. She’s the oldest of three kids . She’s 3 this month.

She humps her teddys or her rug?! I know it’s not sexual but I just don’t know how to handle it. Or what to say! Iv even seen her do it without her knickers ! :/ apparently I could scar her regarding sexual stuff if I say it’s disgusting etc.. advice please?! She’s 3

My other daughters 2 - and a baby who’s 4 months ! My 2 year old doesn’t do it. She mostly hides in her room and does it. And when I ask her she says I’m playing or saying nope nothing.