From a magazine ad.
Luvs is a brand of diaper, that featured images of the Sesame Street Muppets in the 1980s. Created by Procter and Gamble, the makers of Pampers, they were considered a premium brand at the time.
In 1985, plush dolls of Big Bird and Cookie Monster as toddlers, clad in Luvs diapers, were produced as a mail-in promotion with Aviva-Hasbro and the release of Follow That Bird.
Two Sesame Street books were packaged with the diapers in 1987, featuring toddler versions of the Sesame characters -- Tubby Time for Little Ernie and Good Morning, Little Bert!