A "long bomb" home run as first described by Atlanta Braves career player and third baseman Chipper Jones (#10). Mammo is sometimes associated with the term "yicketty" which is a general term for a homerun coined around the same time. Both terms were made popular by the Chipper Jones tweet: (see example)

ones mother

Very large breasts on a female.

Very large and well defined breasts.

Hair on a girls tits and/or nipples.

A grandmother type who is a combination of Mrs. Claus and Mary Poppins. Although she is a person of short stature, she has a heart as big as Texas.