The word is sometimes misused in place of “fleshed” as in, “he fleshed out the details of the story” being written “he fleshened out the details…”

As far as ‘sexually terms’…I think if you reread your own question, you’ll see how easy it is to misuse a word. Your question should have been: “used in any ‘sexual’ terms”, not ‘sexually’ terms. This is how words get misused.

So, unless Websters or the O.E.D. has an entry that hasn’t been posted yet, I’d be willing to bet that “fleshened” has no sexual meaning… unless you choose to misuse it for that purpose.

‘The mind was strong, but the flesh was weak’