Pelvic thrust when being rocked to sleep

My girl does pelvic thrusts when being rocked to sleep lol can anyone tell me if this is normal? I dont know if its a weird way for her to soothe herself or should I be concerned?

She does it after naps too, like if she has had bad nap and woke too early she will cry and thrust against me when i pick her up.

Does anyone else LO do this?