When I started my residency, I was one of only four girls in the entire program. The hospital where I was rotating most of my first year had only male residents.
There were two male residents Nick and Rick in the program who I often ate lunch with and they were constantly fist bumping each other. I honestly can't give you an example of a fist bumping situation. It probably involved mentioning some girls booty.
I started to become intensely jealous of the fist bumping. As a woman, I felt really excluded from it. I used to talk to my husband about it, and whine about the fact that I never got a fist bump. granted, there were other guys who ate lunch with us who didn't get fist bumped either. Mostly, Rick and Nick would just fist bump each other.
Anyway, one day I said something (can't remember what, possibly involving some girls booty) and to my delight, Rick held out his fist to me. I happily bumped it. I was so proud.
Fast forward to nearly a decade later. I did something at work recently that my boss really liked. Instead of complimenting me, he held out his fist and I bumped it. I was only slightly more happy than when I get a raise.
I don't know what it is about having my fist bumped. I just really like it.