It's so confusing!! I use both, but it all depends on the context. When I use "come," it's usually in the context of going somewhere with someone. When I use "c**," it's in erotica writing, where the characters are generally about to do such activities. Sometimes, I can even be sneaky enough to place both forms in the same sentence.
Example: "Hey, babe, come here," Zayn moaned after minutes of silence, "I'm going to c**, and I want you here to see this."
At times, I forget the context, and use the wrong version, but when I edit, I change it if I notice it.