Werehog Instincts + the Starfall Island incident has made Sonic incredibly clingy in his Werehog form. As in "I'm gonna lay on top of you and you're not gonna move me, or else you're gonna feel guilty about it for the rest of the week" kind of clingy.
The clingy you get from cats or dogs who haven't seen you in a week or more and they don't want you to leave their sight
Yeah actually! Although sonic can't transform into a werehog anymore, at least not without some crazy shit happening, he does still have some of the instincts from being a werehog (as well as being a mobian who wasn't raised around humans until he was a teen...) he does basically latch onto someone and doesn't let go. Shadow, especially, after sonic frontiers, since everyone else has been deciding to go on their own adventures, (and while he's happy for them, especially tails, he's very proud of his baby brother growing up) Sonic isn't exactly thrilled about anyone else leaving him for very long.
Plus not seeing shadow— or anyone actually physically except for enemies - for weeks, kinda took a toll on Sonics physce, and he's a lot more physically affectionate now. Though it'll probably wear off after he starts feeling stability again.