Try to seduce her into going along with that nasty stuff you want.

When I tell you in no uncertain terms that my tongue will not be finding it's way up your ass, you refuse to take no for an answer. You just smile, reach up and start rubbing my plump little pussy. My underwear still pulled down around my thighs, you have easy access to my clit. I twitch a little as you brush your fingers across it.

You say, "Come on, don't you ever want to do something really nasty?"

I laugh softly, responding in a small, breathy voice, "...just because you know where a clit is doesn't mean I'm going to..."