The linguistic “process” that allows this is called “expletive infixation” and it, as you might guess from the name, only works with swears.

There’s some neat work on where within the original word you can add them, made all the funnier by hearing people dispassionately dropping strings of f-bombs “to see what works”.

Here’s a classic paper on it: https://scholarworks.umass.edu/cgi/viewcontent.cgi?article=1...