@genR I think that more than the indirect kiss or the action of feeding, it was them being commentes on it by the surrounding girls that made her feel embarrassed.
After all, you can do all the embarrassing stuff that you want without feeling much about it, but it's not until when somebody else comments on it that you truly realize the weight of your actions.
He was handing her the slice of cake using his right arm in page 6 panel 5, but the drawing switches to his left arm starting in panel 6 same page, but more noticeably in page 7. Turns back to his right on page 8.