You could try not getting "In they're good books" first. Because, by the time you do that, then they may very well already think of you as a friend type, and not the boyfriend type.
Try asking them out right off the bat, and maybe you wont have this problem.
"You know that with-holding evidence from a federal officer is a serious crime. Especially when that officer has paid handsomely for that evidence, and wouldn't think twice of ripping that patch off your eyehole and skull fucking you to death."