Tumblebuff is a glitch in Dark Souls which allows you to buff weapons which you normally can't buff with sorceries or miracles such as Magic Weapon or Sunlight Blade. Note that it doesn't work with items such as Gold Pine Resin.
You will get the most damage increase by buffing a weapon with the same elemental damage type as the weapon buff, for example Blacksmith Giant Hammer with Sunlight Blade.
|This glitch abuses the following features of the game:
Have a buffable weapon in your right hand, start an animation such as rolling, queue up a weapon buff sorcery of your choice, switch out your buffable weapon with your non-buffable weapon while perfoming the animation. If done correctly your character will buff your newly equipped weapon.
- Tutorial by UnholyBahamut on YouTube