An injury caused from sexual relations is not related to the genitals. Would usually include a sore muscle from being in a particularly awkward position for extended periods during sex.
Guy #1 "Oh man, my hip is so sore today, I was giving it to this girl last night and her whole body weight was on my thigh during a long period of reverse cowgirl"
Guy #2 "Ouch, I know the feeling, thats one bad sexjury you got there"