All the stuff inside has to go outside. Try not to puncture the guts as previously posted and the rest is easy. I usually don't cut the pelvic bone until after I get to camp. To get everything else out of that cavity I completely gut the deer and then cut all around the anus pretty deeply and then I find a forked stick and break off a fork to be about1"and stick it into the body cavity through to the outside of the anus and then I do a "rotocram" I spin the stick several times and it winds up all the goodies in the pelvic cavity and then I pull it out. The cut anus is usually attached and comes out like a plug with all the connecting tissue. When I get him back to camp I use a saw or hatchet open the bone and clean it out.