Constantly pesters you with the same query, "can I ask you a question?" Never actually asks you the question. If you say yes, he asks you if you're sure and is just super hesitant to ask you the question. If you say no, he will annoyingly try to talk you into it, repeatedly asking if he can ask you a question. 
For example:
Can I ask you a question?
Sure.
Really?
Yeah.
You sure?
Yup.
I don't mean to invade your personal space but...
Just ask the question.
Here goes...can I ask you a question? 