When you hear the Chabacano word chucha, it doesn’t sound like it is a Spanish word. However, according to a book (La Lengua Espanola en Filipinas by Antonio Quilis and Celia Casado-Fresnillo), the Chabacano word chucha comes from the Spanish achuchar.
In Spanish, the word achuchar means penetrar con algo punzante (to penetrate with something sharp). I guess this means poking in English. Wordreference.com defines the word achuchar to shove. In Chabacano, the word chuchar means to shove something in or to insert something. Here are sample sentences of how this word is used in Chabacano:
Chabacano: Ya chucha yo mi dedo na agujero
English: I shoved or pushed my finger inside a hole.
Chabacano: Hinay hinay lang chucha conel earbuds na orejas.
English: Be careful when inserting earbuds in your ears.
Another meaning of achuchar in Spanish is petting (as in making out). It
can also mean to pressure someone to do something. These meanings are
not present in Chabacano though. The disappearance of certain vowels in Chabacano words from its Spanish original is a common occurrence in the Chabacano language.