Displays immaturity to me and should be reserved for the bar or the street.
First thing is no one's paying me to give a presentation. I volunteered my services.
The second is that we have to remember that the best way to educate is to entertain at the same time. If you make people laugh, they pay attention more, they learn more. (I could pull cites for this, but they're locked away in my partner's classroom for summer school). In my case, I tell jokes and I use judicious swearing in an empathic way to shock and spice up what could otherwise be a dry and very dull topic of conversation.
So yes, I swear and I joke about it and make it seem like I'm cussing every other word, but in reality it's a few well chosen spots to goose the audience.
Plus, I quote the great "Inherit the Wind":
"I don't swear just for the hell of it. Language is a poor enough means of communication. I think we should use all the words we've got. Besides, there are damn few words that anybody understands. "