Trouble being one of the guys

I'm a woman in a male dominated field.  I'm not actually concerned with acting like a guy but I would like to stop being left out of stuff.  My boss said to bust their balls and they'd start warming up to me.  So I kiddingly called them losers for not doing something in a group chat.  I thought it was obvious I was joking.  But a couple months later I'm learning a few of them did not take it well.   These guys call each other worse stuff all the time.  So what gives?  Am I reading things wrong?  Are my social skills that poor?