Knuckles could be touchy at times but seemed to have picked up another habit.

He was touchy not in the traditional sense but with you he was more likely to put his hand around your back or shoulder and pull you in to whisper something in your ear, maybe a snarky comment or comeback related to somebody else, or just holding your back while walking around.

But now he had something a little extra.

He seemed to have observed how Amy would run up and hug Sonic from behind, this to him could be a suitable way to say hello to you as well! and that's what he's been doing. Whenever your back was turned you could except a certain red Echidna hastily hugging you behind for a brief time before walking around to face you proper.

He practically slammed into you, almost crushing you with his hug, he really could be expressive when he wanted...