Edit: American English, I should say. The Brits have "bloody".
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...
It also works with "diddly" which isn't.
It's intersting what information can be found out there in this world, even about something as diddly.
https://personalpages.manchester.ac.uk/staff/wendell.kimper/...