Well, I decided not to tell him the truth. I felt uncomfortable with that idea.
I was actually at a lake(not unclothed at the moment, so he was none the wiser), and I basically just said "I'm sorry, but I really just can't", and left it at that. Now that I'm fully remembering the next part, I'm really shaking my head.
As I was walking away, somewhat of a distance, the guy rather unseriously exlaimed "I love you!" in an attempt to get me to pay more attention.
Naturally, this made me move a hell of a lot faster.
I decided to leave very shortly after that. At home, I told my mom to cut my hair on the same day. So for a little while, I had short hair.