I have two netherland dwarf rabbits and one of them does the EXACT same thing, no matter who is socializing with her. In fact I'm about ready to do this with my little bunny girl...
I've read that when females do this they are either wanting to be bred or will do this while being bred. In my research on this behavior I've learned that this has nothing to do with socializing, with people anyway, but with hormones. Getting her spayed can help or possibly getting her a "boy" friend.
I would suggest getting her fixed first as going the route of adding a boy bunny can cause more bunnies or you get one of them fixed anyway, but also because getting her a boyfriend can cause the same behavior anyway... not to mention add more work, cost more, etc. Or, if it's possible, you could try a boy rabbit as they generally have better temperments. Although I couldn't imagine giving a pet up after I've cared for it and bonded.
You can always speak with your vet or a breeder for more detailed answers as my answer here is just what I've learned from researching online and is by no means a "professional" opinion.
Good luck with your rabbit. I hope her behavior changes and your son can have what I know can be a very rewarding relationship with his pet rabbit.