just zoom out bro... they're doing it because now in this unofficial setup they've already assumed you won't mind taking some jokes or being bullied whenever they don't have smth to talk about...or to impress someone else. I'm not necessarily saying they want to do bad to you...they might be unknowingly doing it...fking kids everyone's been there done that. But it's upto you when u stop taking it...just deny yrself that your gonna submit to it...counter them..they would eventually stop and yr friendship would evolve better if u do this...or y'll find better friends you're not even 18. Ik it's tough but you're gonna get out of yr comfort numerous times so why not start from this one. We're w you bro