Bella weeing on Thumper???

:wave:
Bella and Thumper have been together quite a while now and are getiing on really well.Recently ive noticed Bella is tryin to hump him more and yesterday when i gave Thumper a stroke the top of is back was covered in wee!

It was way to high to be his so im wondering if it could be Bella weeing on him while humping to assert her dominance or something.has anyone else ever had this??

Are they both neutered/spayed?

thumper is spayed bella isnt spayed yet but we are hoping to get it done after next pay day.Could it be a territorial thing?