While reading to get aroused (and I assume that's why you read these) do you prefer slang, ie: tit, cock, etc or proper language, ie: breast, penis? Is the use of a word a turn on or off?
Depends on the story. Is it a quickie or a romantic piece?
Slang is much more erotic, evocative and passionate to read as far as I am concerned
your "tame slang" is childish - simply be harsh and dirty.
Penis and Vagina would seem a bit clinical. Otherwise I don't really care as long as it fits with the story.
Cock is my favorite word in a story to describe a penis. Pussy and sometimes cunt. Cunt is a little sluttier which sometimes works very well.