You mean skins? These are for special classes. Pink hair one is probably prostitute when you get high "lady of the night" from working at the brothel. Others I know of are queen (catsuit) for loosing to a draw chick while having high beastmaster rank and fail temptation, schoolgirl for doing "schoolgirl experience" special job at brothel and mare for loosing to a centaur chick while having high equestrian rank. For short visit to the camp just encounter centaur, either "ask for it" or declain fight and prompt to visit camp should pop, for extended one same as with skin mare.