Hello everyone! Sorry about the long post! I need some advice on bonding my bunny willow to my other bun Zorro. They are both fixed and have been for 5+ months. I got willow when she was young and now she is 1. Zorro is a rescue who is 2-3 years old. Willow is a mini lop and is at least 2 pounds bigger than Zorro.
Willow was labeled the ‘Impossible bunny’ by the owner of a shelter when I went to have her meet their buns for a possible bonding. She met about 12 bunnies, male and female, and attacked most of them on sight. The others she ignored till she was mounted and she would attack in that moment. She is very sweet normally and is very vocal when she dislikes something. Anyways, I decided to adopt another bunny in hopes of bonding, but with the understanding I may need to keep them separate if it doesn’t work. I was attracted to Zorros laidback personality. He does not mind being held, will lay flat as a pancake when you pet him and loves to explore and pick at clothes. He is very submissive so I thought it would balance out willow.

They have their own bedroom and they each have half the room with layers of dog pens barriers btwn them to prevent biting. They have done great for the past 3 months. They never bite or fight between the bars and are usually found laying next to each other against bars. When I vacume they always run together.

I took this as a good sign to do short bonding sessions. I brought them into a complete neutral room and let them loose. Willow completely ignored him for a minute and eventually came back to him. They sniffed eachohers faces and butts, separated and then did it one more time. Then willow mounted him from behind. He flattened out and looked uncomfortable and nervous but not like he was going to fight back. After about 10 seconds I removed her and pet them. I put them back in the room after. They continue to lay together.

Today I put them in a carrier together and walked around for a while. I then released them into the neutral room. After a couple minutes willow mounted Zorro. I removed her after 10 sec and she kept going back to try to mount. After 3 or 4 rounds of that I pet them and brought them back to their rooms.

All willow wants to do is mount him. He won’t do anything about it but I’m worried about this behavior. How should I continue and when is enough, enough?