What does rolling mean?

I have a female mini lop. She's 3 months old so not old enough to be neutered yet. Whenever she gets exciting in her cage she rolls in her litter tray - like she's going to flop but just gets up again and rolls again. Does anyone know what this means? Is it a hormonal thing?

Thats one very hoppy little bunny!
"this is the life ahh"
what buns mean on behaviour www.hoppybunnyrabbit.com

Rolling rabbits are happy rabbits!

You have a very happy bun!

My boy Roger often finds his favourite place and sits there for moment, then will very dramatically flop and roll onto his side and have a little nap.

Only a very relaxed, happy bun would do this. You're doing well!

I'm glad to hear it's that she's happy.

I have another rabbit who 'flops' over and has a sleep but I was just confused because this mini lop just keeps flopping over but never stays lying down - just has a good wriggle on her back and then gets back up again! It's very cute and as long as she's happy then I'm happy!