Is this normal??

[cocofigs1]

My bird, Coco, mates with my hand. I've had her for about 1 year and a half, and she does this constantly. I stopped letting her do that after researching it. I have another bird, Figs, who sometimes- depending on the toy- mates with toys. He also mates with throw pillows..? Does anyone have thoughts or ideas on how to stop or teach them not to do this? thanks!