You had a habit of touching Usopp's (your boyfriends) hair. It was full and fluffy- you loved to run your fingers through it.

So, when he was pissing you off one day, you gripped his hair and gave it a firm tug. This flipped a switch in him, his face going red.

"Damn, babe. Don't rip it out, hah?" He smirked back at you, crossing his legs to hide the arousal that your hair tug caused him.