violet, our family is very close and huggers. But there are limits and anything that gives you the "creeps" is ok to set as a boundary. My grandfather was a loving man and gave hugs and kisses, but never kissed my neck. It would ahve creeped me out too.
Follow your feelings, if it made you uncomfortable, maybe you could tell him something like, "I am not used to being touched like that. Maybe just kiss me on the head or something.I would feel better."? idk, not knowing your grandfather, it is hard to say...you would have to make that call. But anything that gives you the creeps, I would consider inappropriate.
I tend to have very keen "radar" now, after all this crap for the years I had it happeneing. Two different people can touch me the same way...identicly the same way...one is appropraite and the other is not...because I feel creepy when it happens There are underlying intentions and I can feel it. Maybe the touch and energy transfer, maybe the look in the eyes, something there causes my inner self to withdraw.
I hope this helped in some small way...please keep yourself safe....hugs...