Pumping....guys are actually usually really cool with it. Think about snappy comebacks if they are the type to tease, like, "So, making milk is my superpower, what is yours?" or something. Or if there is one you are cool with, tell him you are feeling self-concious about it and have him tell the rest of the guys to shut up about it. That is if they are the type to tease. Most are not, and honestly, most men are either just fine with breastfeeding and pumping, or they are too embarrassed to think about it. Or they are too self-absorbed to really care.
You can try muting your pump with a pillow over it. Some pumps are quieter than others. Much as I liked my Freestyle, it was really loud with a very distinctive moo sound. The Symphony, a rental, and the Limerick, a hospital grade pump I own, are much quieter.
Some moms even go pump in the car. That won't work where I live for too much longer because it will get too hot, but some moms do that for privacy.
Worst comes to worst, your right to pump is protected by law, and if they hassle you over it, it could be considered a form of sexual harrassment. It doesn't sound like that things would come to that though.