Question: how to add someone else's bitmoji with yours?
Answer: Open the Bitmoji Keyboard by tapping on the Globe icon. Tap the Friend icon in the top-right corner. Allow access to your Snapchat friends. Select a friend to see Friendmoji stickers with them. Choose a Friendmoji to copy and paste it into your message! Tap the Friend icon again to reset your Bitmoji stickers.