Although usually just done solo with clothes on and just for fun to entertain ones self and friends, it is also possible to carriage naked but then you will need a friend or other object to carriage on. You can naked carriage on somebody's face, breasts, ass or any other body part but carriaging can only be done with a non-erect penis. It is more of a fun play time then strict sexy time.
I just like to Carriage while standing in my livingroom.
"What are you doing?" "I'm Carriaging, try it"
"Carriaging, you are sick" "Dont knock it till you try it"
"Damn, Carriaging is good"
I carriaged the shit out of her face, she loved it but then I got hard so I had to stop Carriaging.