irishbunny has a very good point. It is often really hard to tell how bunnies will get along when hormones are involved. Some shelters around here won't even let you do "bunny dates" with their bunnies until they're a month past their neuter--that's about how long it takes for the hormones to die down. I have tried bonding some bunnies that didn't get along at all (Tony and Benjamin), and although it didn't work out, we did get some good progress.
-Have a semi-stressful situation before a calm situation. We'd put the bunnies in a laundry basket and walk around with it for 10-15 min or so before we put the two in the bathtub for a calmer bonding session. Other options are putting the basket on top of a washer during the spin cycle, taking them for a car ride together. This worked because the "trauma" of the stressful situation made the two come together to deal with it, if that makes sense. There was an outside stressor that was more irritable than the other bunny, so they bonded together to combat it.
-Squirt with a water bottle when you see aggressive posturing.
-Sit them next to each other and pet them at the same time--this can fool them into thinking the other is grooming them.
-Work on it every day.
-End every session with a positive item, like petting them both as above, or a treat, etc.
Like I said, it didn't work out for our guys, and it is best to bond altered bunnies to keep hormones from interfering.
