carrying something on two people's shoulders
Refers to a traditional method of carrying a load, such as a palanquin or heavy object, by two people using a pole across their shoulders. Rare and mostly historical.
In the old days, they carried heavy loads by two people's shoulders.
Compound of 差し (sashi, 'facing each other') + 担い (ninai, 'carrying on the shoulder'). The exact historical derivation is uncertain.