It is kinda ridiculous that when your face (specifically the mouth) is concealed, you can still use Drain Kiss. Like what? How does that work exactly?
Also, I like to give some ideas regarding when your hands are tied up.
Headbutt [STR] - Has a chance to stun an enemy.
Kick [STR] - Has more force and mass compared to using your hands.
Body Slam [STR] - Your whole body is the weapon.
You can use these regardless if you are tied up or not (though, they certainly can be useful when your hands are tied up). That way, you don't have to use Drain Kiss and waste MP.
(These three attacks can be found in the Context button)
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New item: Dirt
If you have dirt in your pocket, you can use it in a fight by pressing the Context button and throw it at the enemy's eyes (you can blind them for a few moves).
Now you are fighting dirty.
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Headlock [STR] - Subdue your enemy and make them unconscious.
You can find it in the Context button. You will sometimes have to keep pressing it since your enemy has a chance to get out from this attack.
Edit: I forgot to add this.
Flip Off - Has a chance to increase the enemy's attack.
There, it is done.