Pit the managers against one another in creative ways for the sheer lulz
Tell the 2nd manager that you'll do what they said just as soon as you accomplish what the 1st manager instructed you to do. You might even quote Matthew 6:24 'No man can serve two masters' to the 2nd manager.
ask the 2nd one to write it down for me so i dont forget because i have to do what the first one asked then i will get to what the 2nd one wanted
i shrugged it off everytime i got snapped eventually my coworkers who i barely knew snapped back on both the managers and the managers check with each other and treat me like the best employee every since
You speak up, to begin with. When the second manager approaches you, you tell him/her, "Mr/Ms. so-and-so just asked me to do _______."
Leave it up to THEM to work out their differences; it's not you're problem. Chances are, the second one was unaware of which tasks you've been given by the first one. That said, it's never easy reporting to multiple bosses.
Ignore them both and do what you think needs to be done.
thats when I have gone to the 2 of them after the fact...obviously and say....tell ya what.....the 2 of you talk this all out and then let me know what im sposed to do.....i CANT follow 2 seperate sets of instructions at one time...yall hammer it out and let me know
Do the items in order so you don't show favoritism. If there is still an issue look for a new job where managers aren't fighting to be favorites cause this job is just going to suck more and more.
Send an email to their joint boss and get them both in trouble!