You can either do the ACT commands "Alpha Remark! - Sit! - Beg!" three times in that exact order, or you can simply open your inventory during the fight and use the Mid-sized Buttplug. Both options will cause Wulfrick to end the fight.
Alternatively, you can bring Wulfrick's HP down to zero by actually fighting him. In that case you need a dagger, so you can keep using skills to ignore Wulfrick's defense stats. Using the "Alpha Remark!" ACT also keeps him from attacking you for two turns, so you can just keep doing that, and use TP gain to refill. However, Wulfrick's got 9999 HP, and at this point in the game, that fight will take you at least 40 minutes, and you don't get anything extra for actually defeating him. For more questions, you can check out the walkthrough.