"cold as a witch's caress" -- very cold

"cold as a witch's tit" -- very cold

a "witch-hunt" -- an attempt to find and punish people who have opinions believed dangerous (e.g. McCarthy's witch-hunt for suspected Communists in America during the Cold War)

Source: thefreedictionary.com

There are sevral types of tits, such as the great tit, coal tit, and blue tit, but there is only one type of blue tit.

There are a number of differences between these two small birds. Firstly the Great tit has a black stripe going down its breast to its tail and the Blue tit only has a small black incomplete stripe. The great tit also has a black cap and the Blue tit has a blue cap. The Blue tit also has more white on its face than the great tit. And a subtle difference is the Great tit is slightly larger than the Blue tit.

The great tit is also different from the Blue tit.

There are sevral types of tits, such as the great tit, coal tit, and blue tit, but there is only one type of blue tit.