Well for me it is simple to explain, why I think that sonic if he hooks up it'll be with amy. He wouldn't need to wear a lash, sure, she is sometimes very clingy, but hey, he is running a lot and you need to show him that you want some of his time.
If he hooks up with her, he would spare much more time for her and she wouldn't chase him like befor. Still he can run, but always would come back around, maybe sooner than he does it now XD
With all the others he wouldn't have enougth space to be still Sonic the Hedgehog, how we know him, Amy wouldn't make him change so much, that he would lose himself over it. So basically, thats my reason. XDD
Everyone knows that a lot of her fantasys are just madeup even because he keeps her on the long leash but never let go of it either....sneaky ass Sonic can be XD