Apantlazalitli means "to go through the water" and it is a reference to a person's birthday feast.
"The natives celebrated each other's birth dates in a way different from our own.Around the neck of the honored one we place a rosary or a jewel, perhaps a golden chain. These people did not observe these customs. Instead, they seized the individual whom they expected to hold a feast because of his birthday. Some took him by the feet, others by the head. They tossed him into the water and immersed him. When he came out of the water, he was bound and obliged to provide festivities for the day. If he did not do so in that year, he would not again be honored, because it was said (with a great deal of scorn and contempt) that he was still bound and there was no reason to celebrate his birthday anymore. This feast was called Apantlazalitli, which means To Go Through the Water, and it is still in use today, and I have seen it observed in certain places. Once the day of the saint whose name a person bears arrives, he is cast into the water, just as was done in ancient times. In some places, however, the natives are becoming more like us." 
- 1971 Duran, Diego Book of the Gods and Rites and the Ancient Calendar, pg. 406