You may find Suzy's boar dating thread helpful; it contains several videos and can help you get a better idea on how boar bonding works. We also have a boar behaviour sticky thread at the top of this section which lists clearly what is normal and what is dangerous behaviour.
http://www.theguineapigforum.co.uk/showthread.php?t=59233
http://www.theguineapigforum.co.uk/showthread.php?t=28949