Яой would be guyxguy and Yuri is girlxgirl. These categories can go anywhere from a single Kiss to sex so be careful and research a show/manga before Ты watch/read it in case it has something Ты might feel uncomfortable seeing. Then there is Shounen-ai (Boys-love literally) which is still guyxguy but there is no sex или harsher activity involved. Only kisses and snuggles are involved here. The same goes for Shoujo-ai (Girls-love). No sexual activity involved except for Поцелуи and snuggling. =] Hope that helped!