As everyone familiar with Roger's Profanisaurus should know, a Dutch oven is created when two people are lying together in bed, and one of them farts and then holds the other's head under the covers until they are foced to inhale. The Profanisaurus entry reads:
Dutch oven n. Beneath the bedclothes after someone has played 'Reveille' on the botty bugle.
Many regional variations are possible depending on (for example) heaviness and/or presence of bedclothes, with a duvet or heavy blanket forming a much more effective oven than a thin sheet. A particularly cruel Dutch chef may confine his or her victim beneath the covers for more than the standard three or four seconds, while the more caring among us prefer to make it a shared experience by joining the partner in the hot zone.
Also known as a Greek Sauna.
Roger's Profanisaurus: http://www.viz.co.uk/profanisaurus/profanis.htm