
WagnerSika |

Get potions of Enlarge person.
Get reach weapon and use your AOO to trip the enemy when he tries to overrun you. Enlarged character with reach weapon has a reach of 20 feet.
Get combat reflexes. If you do not qualify, dip 1 level of monk(you do lose CMB). You get Improved unarmed strike so you threaten adjacent when wielding reach weapon. If your build can afford it, you can dip 3 levels of monk and not lose CMB or CMD (maneuver training). Even better is if you can dip brawler, you can get any combat feat as a move action (you have to meet prerequisites though, except INT requirement)
Three level dip of Lore Warden gives you +2 to CMB and CMD.
Alchemical grease lasts 4 hours per application and gives +5 to CMD against grapples.
Get AC bonuses that affect CMD too, circumstance, deflection, dodge, insight, luck, morale, profane, and sacred bonuses.
Get your party members to contribute too. Oracle gets access to Freedom of movement, no more grapples. Potions of invisbility and later a ring and the oracle is not even a target for those attacks.

WagnerSika |

grace, for trips (to get back up without being tripped again)
You can not be tripped when getting up from prone. The AOO takes place before the action, while you are still prone. There is a faq about it here.
If the oracle is continually the target of maneuvers the Defensive combat trainging feat could be useful.
Your swashbuckler should have really good CMD with his high dex, full bab and class abilities.
Carry caltrops, have the oracle spread some to squares in front of him, no more charges.