My cat is laying on the floor meowing and putting her legs in the air?

My kitten who is about 4 months old, just tonight she started rolling around the kitchen floor then laying on her back spreading her back legs open. The she would roll over and stick her backside into the air. This whole time she keeps meowing and making crying noises. If I go near here her meowing gets louder when she sees me and keeps going through those motions. I know shes not physically hurt so I don't know why she is acting this way.