The first of such conversions happened in 1521 when Rajah Humabon and his queen, Humamay, were baptized into Carlos and Juana of Cebu, respectively. To commemorate this historic event, the local Cebu government thought of creating a Festival in 1980 called Sinulog, meaning "like the water current." How the boy Jesus was linked to it came about this way. Baladhay, Hamabon's adviser, was sick and confined in a room where a statue of the Santo Nino was placed along with other gods.
According to tradition, Baladhay woke up because a boy supposedly tickled him awake. Then they danced playfully together. When asked later who he was dancing with, he pointed to the statue of the Santo Nino and added that the dance rhythm was that of the water current in the river. Thus, the tradition combined the dancing and the boy Jesus plus the river current, and so today's Sinulog.
But true Christianity in the bible is about a spiritual God who has no form and who was made flesh only through Jesus Christ. This Jesus never remained a boy and never set foot on the Philippines in the 1800s. So, it's a good point to always add that Sinulog is a commemoration of how the Visayans embraced Roman Catholicism at the time--not Christianity as Jesus taught it in the bible--because the Santo Nino idea is Roman Catholic, not of the bible.
Every missionary work in the Philippines claims being Christian, but all of them--Roman Catholic or otherwise--carry their own brands of it, not the authentic one that came directly from Jesus Christ and the Acts church. The protestants brought their protestant Jesus, the Mormons their Mormon Jesus, the Adventists their Adventist Jesus, and so on. Within the evangelical lineup, the baptists brought their Baptist Jesus, the Methodists their Methodist Jesus, the Pentecostals their shouting and tongue-speaking Jesus.
Thus, so far, no one has yet introduced the real Jesus of the bible in this country, the true Jesus who came to earth representing the Father's Kingdom (not any denomination) and ushering people to it (not to any denominational church). It's ridiculous how they would all talk about Jesus and not understand each other because each one presents it's own version of a Jesus.
The Roman Catholics have their Sinulog to commemorate their Jesus, while the others, like the protestants and evangelicals, have their own "festivals" they call "church anniversary." But it's a festival nonetheless--with dancing, singing and fanfare. Protestant church anniversaries are commemorations of how the denominational church was first embraced by people in a locality, just like what Sinulog is to the Visayans.