My boyfriend and I use nicknames on each others’ animals. He has a dog that has several names from me- Mr. Goodboy, Handsome prince while he just calls him buckathon, bucksauce (various versions that include his name buck). My two cats are just trash goblins, little floofers, or chonksters to me but he’ll call them weird versions of their name like icepick (her name is isis) or grayble(his name is grayson). Its very cute!