Look up adulrty. If you lust you're doing it. Sorry do the rules make you uncomfortable? Do you even know the rules? Clearly not.Sorry, this is a fallacious premise. There is no "thou shalt not fantasy" Commandment. Doesn't exist.
And no, covet doesn't cover it.
I have a Dulrtry in the next town. They spell it "Dollar Tree". Nothing lustable in there though.
There's no biblification against lust. If we didn't have lust we wooden exist.