I'd kick him in the arse and ask 'Why, after all those years, did I never win? Why? WHY?!?"

I would say your SONIC!!! Can I join your Adventures!?!!?!?! and after that it depends on his answer (I could be a person who plans tactics and stuff) :)

I would rip out his still beating heart and devour it to gain his courage, his strength, and his speed.

Beat it to death with a stick, cook it over an open fire.

I would treat him to a nice dinner and I would pose for selfies with him and I would give him my Email address so we can always communicate with each other.

I’d tell him I’m not one of...”those” fans..... the fans who do weird fanfics,weird animations,and all types of weird stuff. And the fans who do weird stuff who are oblivious to the fact that they are doing it. I’d ask him many,many,questions until he’s not in the mood for it no more. If I ever do the weird type of sonic things I’d just be doing it to be derp and memey. Because.....because.

I would most likely chat with him a little, and after that try to figure out how he can possibly run so fast. I would most likely get a CATscan of the muscles and tendons in his legs to do that. If he annoyed and disrespected me, I would try to capture him like Robotnik in AoStH. If he didn't I would probably let him go free, though try to get a blood sample so I could examine Sonic's genome (if I got the proper equipment) and then load it into a cell-printer to see if I could successfully make a clone of him.