Before: Pookers was with Medusa. Friendship relationship, no dominant bun. He groomed her more.
Now: Pookers is with new gf Dakota. She grooms him more. He never mounted her. She mounted him one in the beginning.

Their introduction went really well and they lay together and stuff. Now his parents are informing me that he is nipping her when they pet Dakota. Read their account:

Pookers nips dakota in the rear, never turns into a fight and they continue to groom each other. We have notcied it when they are together and we are petting one or the other, more dakota. I have watched them secrectly and they dont do it when we are not around or petting them. But I or janee reach down and give dakota a quick pet he nips her. it is literally after we pet dakota, or show some sign of affection towards her.
*****
I was thinking it could be 2 things:
1) Stress in adjustment to the new home and new gf. Attachment to Medusa still.
2) He wants to be dominant.

Any new ideas? They have been putting over the dryer and stuff to encourage bonding.

Not sure if this is going to help at all, but our bonded trio is 2 girls and one boy.  They have been together for three months now, and Curly Sue still nips Deanna sometimes.  Usually it is either because Deanna is nice and relaxed and on a mat that Curly Sue wants, so she nips her back legs, or Deanna is grooming DJ when Curly Sue will nip Deanna.  These are nips, right?  No fur pulled out and no blood drawn?  They may still be negotiating about who is boss, and what the relationship with the humans is going to be.

Nipping on the rear usually is an indication that one bunny wants the other one to move. Jack gives Rucy very gentle nips on her bum when he wants to be left alone in the litterbox, or when she's blocking his way to get out of the pen.  

He may be wanting her to move away so that he can be given a turn to be pet. 

If he does it in a very aggressive way, then it looks like they are still working on parts of their relationship. 

They should be sure during this time to give them both equal amounts of affection, so he doesn't feel threatened that she is being considered the "top"bun.

 

It sounds like he is being top bun over there. Weird because w/ Medusa they were equals and if one of them had to be top bun it would've been Medusa!

hahaha girls are top. =P jm sometimes i get little nips when one of them wants more attention or more treats (cant give in though) either that or they nosepoke me.