Razzing is playfully roasting someone or teasing someone. It could often be a close friend or family member.
It could be over anything but it could be brought on by something that might be revealed by a
person that is a surprise to others. Something that could seem out of character.
Like a
guy finds out his very tough and rugged friend really likes love songs or romantic movies.
His
friends might razz him over that a little bit for fun.