Lots of options here but my favorite is to use an elevated metal grate, as used for steaming, at the bottom of a pot, then put the sandwich on the grate. Put a few drops of water in the pot, cover it, and put it on low heat for as long as it takes, usually 5-10 minutes.
The low heat and extended time gives you a thorough heating all the way to the middle. No direct connect to the pot, so the bread doesn't get burned.
Adjust the "few drops" of water up or down if the bread gets too dry or too soggy.
That's kind of the opposite. You're talking about using "female" as a noun instead of an adjective. And for sure, don't do that to refer to humans! But it's perfectly normal and correct as an adjective.