Yes, as J&B says, I’ve always found bunnies wee on soft stuff. The only exception was my bridge bunny Boots Frosty and Fern usually reside in a cat tree tower each, sometimes in the same one but usually they go in different ones, so I wouldn’t worry about the bond. On the subject of the cat tree, *whispers * they have never done a wee on or in there, that’s kind of fleece material stuck onto wood. Apparently it’s very comfortable for a bunny to sleep on, so fleece or blanket stretched over something might work:? I think something quick drying like fleece or something like vetbed might be good.