* Hisses: This is the plural form of the verb "to hiss," meaning to make a sharp, sibilant sound, like a snake.
* His ses: This could be a typo for "his says," which is a grammatical error, but might be used colloquially to express someone's opinion or statement.
If you could provide more context, I might be able to give you a more accurate answer. For example, what sentence was the word in?