Do as goris do when they are about to receive an unwanted kiss. They don’t push anyone, they just stay alert to the person who approaches them and as soon as the person starts coming closer they wave their finger like :nono: and the boy gets the message and no one feels awkward.
But I think you shouldn’t think of hugs as a sin as in western countries it is an act of showing respect to the women. If you are showing a dislike of a simple hug who doesn’t know why you dislike it, then you are offending that person more than he is offending you.