Here are some examples of double interrogative sentences:
1. What why did you tell me that?
2. Who where were you yesterday?
3. When where why are you going to the party?
4. How what did she make the cake?
5. Which who did you give the book to?
6. Whose where is the umbrella?
7. Why where did you leave your phone?
8. When what why are you coming back?