You definatly can test with just a toe. I have used this one before: "Hey, did I tell you about my friend? He's married AND he has a girlfriend. Kinda different huh? No, he's not cheating on his wife. She KNOWS he has a girlfriend and she has a boyfriend! I think it's kinda cool, and my wife and I have thought about it a lot."
At this point, see where the reaction is. If she's totally turned off by the thought, then move on. However, if she is inquisitive, then forage ahead.
Good luck and keep us informed.
There is a lid for every pot...Sometimes even two or three...