The Adventures of Lion and Nip
So I'm thinking that the last book in the series will be titled Nip Goes to Live on a Beautiful Farm in the Country, and the cover will show the giant breast collarless and leashless and being tossed unceremoniously from the window of a speeding car. Closer inspection will reveal that Nip has thrush AND mastitis AND nipple trauma and is looking a little fat for her pants. Really, it is Nip's time to go live in the country. Also, Lion is twelve years old and enough already.