WHATS UP WITH HIM.......???? help plssssss?

This guy have been waving and smiling at me and i think he is interested in me. I always smile and wave back and i even inquired abt him to a colleague...he probably think im interested too or just being nice. Recently i think he told his friend abt me and since then the friend alywas say ''hi!!' and ''good morning''!! in a palyful manner and the guy will just look down or laugh childishly...i just smile back.. he seldom wave anymore...its like his friend's doing the work and he just laugh along.. are they teasing and laughing AT me coz they;re playing a fool OR is he teasing the guy abt liking me?? this guy's VERY loud and talkative with friends but when he;s alone with me somewhere he'll be very modest and shy and awkward..... i still need to know whats gg on before i make a move..do u think he likes me or im just the only one being fooled..?? and..how should i react the next time i come across him and his friend??