I know it might be cold and lonely in the 59405. But that's no reason to get irrational, or your hopes up. It's a dude. It's the FBI. (Here, his name is Dan.) It's not who you think, and not someone you want to offer to have sex with. Much do you want to offer to pay the person for sex, and to pay more if "she" can find another 15-year old to have sex with you too.
This advice comes too late for Mark Christensen, who now gets to spend the next 17-plus years or so in the federal pokey. Live and learn.