Our 8 year old daughter walked in on my wife giving me oral sex. We immediately sent her to her room. But now she keeps asking questions. What should we tell her? 

While you might not have chosen to discuss oral sex with an 8 year old without such an incident, since she did see you doing this you don’t want to leave too much to her imagination, especially since you know she’s thinking about it as she’s asking questions. On the other hand, you don’t want to necessarily tell her too much either. So what you have to do is listen to her questions and answer them in as limited a way as you can. If she asks for more information, then you have to keep answering her questions, but hopefully you can answer what is bothering her without going into too much detail, though there’s no guarantee of that. 

The important thing is to make sure that she knows the two of you were showing love for each other. You don’t want to leave her with the impression that something awful was taking place. And remember, she might be discussing this with her friends, and you can’t tell what she is hearing from them. That’s why you must make sure that she gets the correct information.

I know such discussions are difficult. You might want to buy an age appropriate book on the subject of sex and read it together. That will make it a little easier for both of you. The book may not bring up the subject of oral sex, but you can then place what you were doing in the proper context.