Resolved questions
The proper and polite way to request a person 8 year older to speak 반말?

Please let me know the exact sentences that I should say.

A friend of mine is 8 years older than me but keep using 존댓말.
I'm a bit uncomfortable... having an uneasy feeling...
I just want to convey the idea that "You please use 반말, and I'll definitely continue with 존댓말."

Thanks for helping out.