油 oil

I have the freedom to splash Your Underpants with a liquid called oil.

let down your guard. ★★☆☆☆
油 (oil) + 断 (decision/judgement/refuse) = 油断 (let down your guard.)

soy sauce ★☆☆☆☆ KANA

soy sauce! (usually KANA, so I'm just giving it *)