Mochila

[Sarah]

A large leather flap which covers the saddletree. [WesternU.S.]

[Sarah]

1. spanish word for 'backpack'

2. in english, a very rare and exotic name/nick-name for highly selective individuals, including the remarkable fellow, Hansen

[Sarah]

Used as a term to call someone who hangs on their boyfriend/ girlfriend all the time, thus acting as a backpack.
This person is characterized by asking for constant piggy-back rides, always hugging, or attached in some way to their boyfriend/ girlfriend. This happens often enough to become awkward to other people near-by.
A Mochila is generally female due to mochila being a feminine word in the Spanish language, but is not at all uncommon in males.