Newspost!
Despite what Blake is saying here, it probably wasn't actually "porn and sex toys" that he was going to write on the box. If it were that simple, he'd probably have just written it before Charlie noticed and bawled him out.
But it was probably something that would've been equally obvious. Like "novelties" or something else that many people use as a euphemism for porn, sex toys, or all naughty things. When he speculated aloud about what to actually put, Charlie took issue with it (probably because he didn't want to be nearby if Blake's parents noticed that label and started asking questions of their dear son).
Now you know!