Also I can’t imagine this was a regular occurrence

So far as I know, this is the only occurrence of it happening.

The Iazyges were conquered by the Romans on land at this time and later on the river. By this I do not mean that any naval battle took place, but that the Romans pursued them as they fled over the frozen Ister [Danube] and fought there as on dry land. The Iazyges, perceiving that they were being pursued, awaited their opponents’ onset, expecting to overcome them easily, as the others were not accustomed to the ice. Accordingly, some of the barbarians dashed straight at them, while others rode round to attack their flanks, as their horses had been trained to run safely even over a surface of this kind. The Romans upon observing this were not alarmed, but formed in a compact body, fa­cing all their foes at once, and most of them laid down their shields and rested one foot upon them, so that they might not slip so much; and thus they received the enemy’s charge. Some seized the bridles, others the shields and spearshafts of their assailants, and drew the men toward them; and thus, becoming involved in close conflict, they knocked down both men and horses, since the barbarians by reason of their momentum could no longer keep from slipping. The Romans, to be sure, also slipped; but in case one of them fell on his back, he would drag his adversary down on top of him and then with his feet would hurl him backwards, as in a wrestling match, and so would get on top of him

-Cassius Dio, 72.7