Okay so I was talking about this with @neverkncw, but with my last headcanon about Craig in college about the Frat Brothers that made him feel insecure, he's got a loooot of scars on his body. They're very light and small, but he thinks that they're bad so he gets hesitant when someone finds parts of his skin that are uneven or raised. He's afraid of his partner judging him. This is also why he has been working so hard on his body. So if his partner traces them, or even sticks their hands up his shirt, he'll jump to grab their wrists at first but then pass it off as nervousness and hope they haven't noticed. This isn't about him, it's about how he makes his partner feel.