give a pink flower(or any flower) to sparrowtail, she will ask for you to talk to milkywillow, talk to goldenstrike, talk to them kits(you will know what im talking about...) and boom
i dont think you CAN have kits with them, idk check the wiki, also kits appear in the nursery, i know where the fallenclan nursery is btw(it was difficult to find lol)
