I scream and yells that he/she must go away and you get really mad at yourself for this to happen
Don't care. it's not like the kids will be rapist or anything of it
Talk to the kid and says that it is adult stuff but totally normal
Call the kindergarden, family, friends and everybody who will talk with the kid and explain why he might will talk about this and that it is not like the kid is beeing violated sexually (while shaking and swearing to yourself)