20 month old self soothing habit question!!

sherry

Okay so for the past few months my 20 month old daughter has developed a self soothing method. She “humps” or does that movement when she is tired or bored I think. She will hump my husband and I’s arm or leg for what seems like hours even though we tell her to stop or we don’t do that to mommy or daddy. I think she continues to do it because she finds it funny. Has anyone been through this with their little one? What do I do?