I've never seen those big tricycle things before, but judging solely on this video, those are a terrible idea.
It's a baby rabbit, It's pawing it's mothers teat to stimulate the milk.
The babys rabbit is cute :)
Cats do it too. That's why when even adult cats are happy, they like to knead your arm, or lap, or tummy or...you get the picture.
i made this funny edit :)https://www.youtube.com/watch?v=HjpMVRfM7U4