This is how I use "come":

Joel moaned panting, his legs shaking as he stood, and felt the urge to come bubbling inside him and he shook his head, not ready to come just yet.

I actually rarely use the word "c**"--I prefer writing something like "releasing sticky fluid" because I think c** is too slang for my writing--but when I do, it's a noun:
“You better not get c** in my car.”

It's not often we get to academically debate the proper use of "come" vs. "c**". xD