Not sure what you mean about your go including two words unless you mean like adding a word ending in 's' etc onto an existing word. The rule I think you mean says' When two or more words are formed in the same turn, each is scored. The common letter is counted (with full premium value if any) in the score for each word.' The first player will have a double word score as a letter of the word has to be on the middle, starred , square and that's a double score square.