Strictly speaking, this term is reserved for those females who in spite of their thick complexion are sexy enough for a romantic encounter. Just like "MILF" designates the "oldies but goodies", gordibuena characterizes the "chubbies but sexies". Gordibuena does not identify the specific nature of a woman's attractiveness (cute face, nice chest, fun personality, good dancing skills or meneo, etc.). Instead, the term only denotes approval of a pass/fail test.
Beauty is in the eye of the beholder. Moreover, beauty standards drop significantly in the presence of alcohol. For these reasons, the term is often abused and used to justify one's low passions and bad taste.
Pablo: No manches carnal, te esta buscando Greenpeace porque ayer mataste una ballena!
(Dude, I can't believe you made out with that fat-ass last night!)
Armando: Pus segun yo estaba gordibuena!
(Oh, give her a break! She had a nice smile and an awesome personality!)
A similar way to say a girl is gordibuena is to say: no esta gorda, solo tiene huesito ancho (she's not fat, she only has thick bones). Mexico's cine de ficheras (low-budget sexi-comedic movies) has been the principal media which shapes and defines the aesthetic standards of the term gordibuena. The photo above displays the dangerous curves and charming personality of the famous actress Rosa Gloria Chagoyan (aka Lola la Trailera).