The head dress better known as a niqab or the person who wears such a garment. It refers to the eye slit in the head dress being similar to the slot you would put toast into.
The term also refers to a Cylon, from the TV series BattleStar Galactica.
In 2010, France became the first European country to ban full face coverings, including a niqab aka Toaster Oven, in public areas.
Similar to a dutch oven, a scouse oven is the act of farting in someones face under the covers. Rather than pushing them under the covers and holding them there to force them to smell your gas you have them willingly co-operate in the act by getting under the covers, getting their face behind your bum and staying there while you fart in their face.