Where does “me cago en la leche” come from?

me cago en la leche (Spanish) comes from Spanish leche, from Old Spanish leche, from Vulgar Latin lactem, from Latin lác, from Proto-Indo-European ǵlákts — milk.

me cago en la leche (Spanish): I shit in the milk

Definitions

I shit in the milk

Ancestry of “me cago en la leche”, step by step

Step	Language	Word	Meaning
1	Spanish	leche	milk; cum, semen; shit
2	Old Spanish	leche	—
3	Vulgar Latin	lactem	first-person singular present active subjunctive...
4	Latin	lác	milk
5	Proto-Indo-European	ǵlákts	milk

Every word from Proto-Indo-European ǵlákts →Every word from Latin lác →Every word from Vulgar Latin lactem →