Literal translation
To carry the satchel
Meaning
to take along a picnic
Explanation
The biasso is the bag of the hunter, the farmer or the fisherman, the one they carry their packed lunch in. The word shifted from the container to the contents, a classic metonymy : one says manja la biasso, to eat the bag, hence mena la biasso. In a mild climate where people like eating outdoors, the gesture is so everyday that it passed as is into regional French. The verb mener meaning to bring along is a calque of the Provençal mena, which also means to drive or lead.