The story I made behind this is that sometime during the Classic era, Sonic and Tails get invited to an event (probably involving an award in their achievements), and reading the invitation Sonic reads aloud “attendants must wear formal dress attire.”
Course the 4 year old Tails (I like to think Sonic was 11-12 in the early and mid Classic era), misunderstands and asks if they have to wear dresses.
Sonic’s reply is, “nah they mean we gotta wear fancy clothes, but you can wear a dress if you want to kiddo.”
Tails gets exited with a “boy do I!” as reply so Sonic fancies the little fox up. Sonic then joins in the fun accompanying his outfit with these shoes here.