I carry my lance in Posta Dente di Zenghiaro (Boars Tusk Guard) because I am well armoured, and have a shorter lance than the player, so I can beat his lance offline diagonally upwards. And if I strike with my lance an arms length along the shaft, my lance will find his body and his lance will pass offline away from me. In this way I will do it.
Carrying the lance low like this allows you swing it it diagonally up, knocking the players lance offline and leaving yours on target. There is a degree of timing required to get this to work well. Aim to contact the players lance in the middle of the shaft for best effect.