It looks like an extremely well calculated move to wait until she started to accept that her crush has no hope, get somebody else to point out his lust for her to shock her, and immediately kiss her while she's in a state of confusion and maintain that confusion with said kiss. Getting Jill out rather than ogling him sucking her face off becomes a higher priority than smacking him for stealing her first kiss like that from the only person in the room able to keep a cool enough head to tell him off for his actions.
In a shoujo this is normal human courtship. Elsewhere, these are the clear actions of a predatory older male taking advantage of a teenager's emotional turmoil and immaturity to have his way with her while she is incapable of understanding the difference between lust and love.
It's unfortunate that all of her advice comes from the inexperienced peanut gallery right now. An older woman could have pointed out that kisses are SUPPOSED to feel good. Them feeling good has no little connection to if you actually love somebody.