So the wrong thing to say

Recently I was helping out in the warehouse trying to get a job done that was extrememly hot and had to get out the door. Basicly it was one of those jobs where the machine is running on max and every employee on first shift is busting their butt and doing whatever is necessary to keep up with the machine. We were all working on "Maximum" until the second shift came in where there was a short delay in overturning the employees. When a female employee came over to the machine and asked if we were ready to get going, my boss, needing a short break, tells her that we need a quick 5 minute "blow" before continuing. Just about everyone in earshot looked up at hearing what my boss said and starting laughing. He said it innocently enough, just needing a break, but it was so the wrong thing to say. Making the situation even funnier is that the co-worker is gay so her comment back to my boss was, "you are talking to the wrong person for that". So after a quick 5 minute break it was back to the machine a little red faced.