Do a zebra roll!
The other guys don't seem so amused. 😃 But do zebras do this sort of behavior often? Is it scratching an itch, or rubbing dirt on itself as sun protection?
I don't know about zebras but horses (a close relative) do it ALL the time, especially in the heat with the flies 😃.
It could be either scratching an itch or trying to dislodge parasites, or just because it feels good.