Recently I was thinking about the verb to weed, so I was interested to read a post today on Language Log about verbs that mean removing the thing that is named, for instance to bone a piece of meat, to gut a fish or to string a bean.
The post also refers to pitting a cherry and says this is why this type of verb is called a pit verb. I would not use the word pit to refer to the seed in a cherry. I'd use the noun pip instead, and I think this is probably standard in Australia. But if I needed a verb for the action I'd say I was going to pit the cherries.
I definitely wouldn't say I was pipping cherries.