Pls help me. How do I wash her hair.

My 16 month old screams bloody murder every time I try to wash her hair. She doesn’t lie back or even sit down in the bath tub. It’s always a standing bath. Neither does she let me put on one of those visor caps to avoid the water and soap getting in her eyes.

I’ve had to sit down on a stool and lie her in my lap to wash her hair so the water can run down when I wash the shampoo off. But the whole time she was crying and flailing.

I am at a loss. How do I do this? Please help!

(No the water isn’t too hot or cold. One day she just suddenly hated getting her hair washed..)