See, I read somewhere that there are two main kinds of swears: Those having to do with bodily functions and actions, and those which are intended as a insult to people based on genetic characteristics (race, sex, ethnicity, etc.).
The former comes out of my mouth as fluently as any other word in the English language, mainly because they have strayed so far from their original meanings that they aren't offensive in my mind. Seriously, in real life, I drop enough F-bombs to obiterate the entire hemisphere (well, if they were actual bombs). I will almost never use the latter. At all. Those actually DO offend me. Funny, huh?