Herpes on the buttocks is still genital herpes. You shed from the area of the actual lesions when you have them as well as also from the entire anogenital area. In between obvious lesions, you shed the virus periodically from the entire anogenital area and not from the area where you typically so far have had obvious lesions at. The skin on the buttocks is too thick for the virus to shed from without obvious lesions present. so what this means is there is absolutely no difference between your infection and someone who typically gets obvious lesions on their actual genitals. make sense? so if your partner doesn't have hsv2, avoid sex