Both are correct. There's no grammatical preference. I had to look it up. I think 'spat' might be becoming outdated, and the word 'spit' is used both as the noun and verb. "There is spit on the floor." "I spit on the floor." Hmm, in further thinking though as I write this, if you say, "I spit on the floor.", there is the possibility for miscommunication as to whether or not I am currently spitting or that I have spit. If I say, "I spat on the floor.", there is no misunderstanding. It's clearly understood that this was a past action.

In standard English, the past simple form of 'spit' is 'spat'. You will find this in all grammar books, and this form is indisputably correct. In a few books and verb lists, you will occasionally find the alternative form 'spit'. This is an older variant which was used in England in earlier centuries, and today it still persists in some regions of the USA. It is not used anywhere else, and sounds wrong to the majority of English speakers. You should accept that certain variations and non-standard usages exist, but you shouldn't copy them.

I believe both would be understable, but the second is grammatically correct I believe.

I agree with Farhan

As dua afirmações não estão bem colocadas.... Cuspir está conjugado no infinitivo, por tanto, o correto seria dizer "ele/ela vai cuspir ..." ou algo como "ele gosta de cuspir..." A segunda frase está no passado, por tanto, o correto seria dizer algo como "ele/ela cuspiu" ou "ele bebeu algo que não gostou e cuspiu em seguida"