u/ManufacturerVisible

Amy is really the only girl makes Sonic feel emotions that he never express before, compare his relationship with the other girls, he shard the same energy with Tangle

He's chill with Blaze he's play off with Rouge flirting behavior, but with Amy he's get nervous flustered overwhelmed shy by her , because Amy shows affection clingy and handsy , she the only girl that does this with him and he doesn't know how handle it

You will never see him act this way with other girls

because Amy is the only one who made him feel this way, she gives him attention she wants to socialize with him, she wants to spend time with him,

Everytime she expressed her feelings for him in public he gets embarrassed, he gets nervous everytime she gets handys, he feels things he never feel before

is ashamed some people just assume he doesn't like Amy they think he's disgusted with her, which is not true, he's overwhelmed by her affection behavior

he's not used to someone wanted to get close to him

wants a realtionship with him romantically, that's why I like his charactztion in the game's better than his version of his himself in other media when he's portal as a playboy, I like the idea of him struggling wanted to take the step further with someone that he cares about, he's still have a heart of young guy but will become a man later on.