Lovely Bunny... Its a normal bunny who is very comfortable. Its call a bunny flop. Normally a bunny who is very comfortable where he is will do it.... just sort of flop on its side to rest..... mine do it all the time. Bunnies are prey animals that are mostly always on guard. so its nice to see one do a flop it means he feels no treat in his surrounding and is very comfy.
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Your bunny remimds me of my Bridge bunny Sebastian who i lost last year at age
9.5 years. Looks almost like your baby.